Core having superior end face insulation and method of treating core end faces to give insulation coating

ABSTRACT

A means for treating the end faces of a core which is used for an electrical apparatuses and etc., to give insulation extremely superior in effect of improvement of the insulation, corrosion resistance, adhesiveness, heat resistance, and magnetic properties at a low temperature in a short time without cleaning for removing punching oil, annealing, or other pre-treatment; a core having an insulation coating comprised of a dry film of a pure silicone polymer, modified silicone polymer, and/or mixed silicone polymer as a silicone compound on the core end faces and having an average film thickness of at least 0.5 μm, a breakdown voltage of at least 30V, and a heat resistance in the air of at least 400° C.; and a method of production comprised of forming a core, then dipping it in or spraying it by one or more types of a pure silicone polymer, modified silicone polymer, and/or mixed silicone polymer as an insulation coating.

TECHNICAL FIELD

The present invention relates to a core having end faces, caused bycutting, punching, etc. the core in the process of producing a coreusing magnetic steel sheet, treated to be covered by an insulationcoating extremely superior in insulation, adhesiveness, corrosionresistance, etc. and a method of insulation treatment for the same.

Further, the present invention relates to a core of electricalapparatuses on which silicone compounds having Si—O bonds coated anddeposited so as to improve the properties and prevent short-circuits anda method of production of the same and to a high temperature operatingelectrical apparatus and method of production of the same.

Here, the “transformer” is an electrical apparatuses which are motorcore, generator and transformer in the broad sense of a stationaryapparatus produced by stacking or winding a magnetic material andincluding a high frequency band used for changing a voltage. The“magnetic material” means oriented magnetic steel sheet, non-orientedmagnetic steel sheet, amorphous metal, permalloy, and other known softmagnetic materials having ferromagnetism used for large-sized tosmall-sized transformers.

BACKGROUND ART

When using non-oriented magnetic steel sheet for a motor core orstationary apparatus, the core is made by slitting a magnetic steelsheet coil, punching it into predetermined shapes, stacking apredetermined number of these shapes, then clamping them by welding,calking, bolting, band clamping, molding, bonding, etc. In the case ofusing a transformer core made of a grain-oriented electrical steelsheet, the strip coil is slitted, cut or punched into a predeterminedshape, and thereafter these shaped sheets are fabricated to stacked coreor wound core. Transformers come in roughly three types:

1) Mainly medium-sized to large-sized “stacked transformers” havingoriented magnetic steel sheet stacked to form a core

2) Small-sized “wound transformers” having oriented magnetic steel-sheetor amorphous metal wound to form a core

3) “Small-sized transformers” including switching power sourceattachments attached to apparatuses having mainly non-oriented magneticsteel sheet, oriented magnetic steel sheet, amorphous metal, andpermalloy as stacked and wound cores (EI cores etc.)

Medium- and large-sized transformers called “stacked transformers” of 1)are transformers used in ultra-high voltage substations and primarysubstations to intermediate substations. They are produced by stackingoriented magnetic steel sheet and fastening them by bolts and nuts orspecial tape or if necessary annealing or varnishing and attachingwindings.

Small-sized transformers called “wound transformers” of 2) aresmall-sized transformers for power distribution use positioneddownstream of intermediate substations. They are assembled by windingslit oriented magnetic steel sheet and amorphous metal to apredetermined size, shaping this, then strain annealing, again shaping,then winding conductors.

The EI cores and other small-sized transformers attached to electricalapparatuses of 3) are not limited to oriented magnetic steel sheet andmay also use non-oriented magnetic steel sheet. They are formed bycutting or punching the-sheet to predetermined sizes, then stacking.Sometimes they are also produced by winding.

Note that the above distinctions are peculiar to Japan. In othercountries, particularly in Europe, there is no classification of 2).This is considered a small-size of the classification 1).

All transformers basically mainly use magnetic steel sheet or amorphousmetal as the material for the core in order to secure efficiency.

Among these, magnetic sheel sheet is produced by steelmakers. The finalform in the steelmakers is normally coiled steel sheet of a thickness of0.20 mm to 0.70 mm. This is slit into the necessary width, then furthercut into the necessary lengths and cut into the final sizes.

The surface of magnetic steel sheet is normally treated to give it aninsulation coating. Varnishing and bluing are performed with the purposeof improving the corrosion resistance and insulation of the end faces ofthe core (surfaces formed by punching, cutting, etc.) The surfaceinsulation coating of magnetic steel sheet used in this way has aneffect on the corrosion resistance, punchability, weldability, andinsulation. In particular, much research regarding improvement of theinsulation has been performed from the viewpoint of improving theinsulation between steel sheets at the time of stacking so as tosuppress an increase in iron loss due to eddy current loss.

In the past, as the insulation coating agent for the surface of steelsheet, an organic type coating agent have been used in a grain-orientedelectrical steel sheet, and an inorganic type, organic type, andcomposite inorganic-organic type coating agents have been used innon-oriented electrical steel sheet in accordance with the applicationof use or objective. An excellent heat resistant insulation film isrequired for a grain-oriented electrical steel sheet because forsteritefilm formed during secondary recrystallization annealing on the surfaceof the steel sheet and therefore heat-flattening treatment at 800–900°C. must be done to coil-set and to remove stress. In addition, agrain-oriented electrical steel sheet has a considerable improvement ofiron loss and magnetic strain by film tensioning effect. As mentionedabove, an organic type coating agent as the insulation coating is notsuitable for a grain-oriented electrical steel sheet. In general, aninorganic type coating is superior in heat resistance and weldability,but inferior in punchability. On the other hand, an organic coating issuperior in punchability and adhesiveness, but inferior in heatresistance and weldability. In recent years, to eliminate the defects inthe two, composite inorganic-organic type coatings able to exhibitperformance between the two have come into general use. With only theinsulation coating formed at the time of producing the steel sheet,however, the insulation becomes insufficient or, in the case ofincluding an annealing step, the insulation drops considerably, sovarnishing or other insulation becomes necessary.

In particular, in recent years, it has been discovered that theinsulation at the end faces of the core formed by punching or cuttinghas a large effect on the core efficiency. There has been rising demandfor development of an industrially superior technique for treating theend faces of cores. With the method of insulation treatment of the endfaces of cores used generally in the past, however, while considerablyeffective for improvement of the corrosion resistance or insulation, theadhesiveness, coating strength, and insulation have been insufficient.

For example, bluing not only results in poor insulation and corrosionresistance, but also inferior stability and gives rise to tremendouscost increases in the heat treatment step.

Further, treatment by an organic compound or a varnish comprised mainlyof an organic compound is effective in its own right for corrosionresistance and insulation, but is insufficient for adhesiveness, coatingstrength, insulation, and heat resistance. In particular, the problem ofpoor wetability means that cleaning or annealing is required aspre-treatment. Further, for heat resistance as well, this is unsuitablewhen the process of formation of the core includes aluminum diecastingor other heat treatment.

Further, treatment by phosphate or another inorganic-type insulationcoating, like treatment by organic type and semiorganic type coating,requires pre-treatment and requires high temperature drying. In coatingperformance as well, there are the problems that thick coating isdifficult, the adhesiveness is poor, the insulation coating detaches dueto annealing, etc. These prior art have had many problems from theviewpoint of the work environment and efficiency and further improvementis desired.

Further, phenol resin laminates, silicone resin laminates, molded phenolproducts, and other synthetic resin insulating materials are used asinsulators, but these are not coated directly on the end faces of thecores, but are wound or adhered as finished products and thereforecannot prevent drops in insulation due to burrs etc. of the end faces.

Further, in recent years, transformers using amorphous metal as thematerial of the cores have also been produced, but in the production ofthe transformers, due to the “weak stiffness”, at the time of “coreinsertion (lacing)”, temporary fastening is performed due to the“tearing” of the amorphous foil. Measures for prevention of this“tearing” are necessary. The cores of the completed transformers aremainly dipped in oil, but the temporary fastening and fixing solutionused for prevention of this “tearing” requires oil resistance. There areinherent limitations on the properties sought from the viewpoint of workefficiency and labor health.

As electrical apparatuses, there are motors, actuators, generators,transformers, reactors, and other electromagnetic apparatuses or heatersetc. Electromagnetic apparatuses are generally comprised of conductorsfor carrying a current and a magnetic circuit for carrying magneticflux.

A large amount of current is passed through the conductors to achieve ahigh output of the electromagnetic apparatus. If a large current ispassed through the conductors, however, the conductors or peripheralmaterials are heated, the electrical insulation of the conductors ormagnetic materials is destroyed, and problems arise in fastening themembers of the apparatuses.

The magnetic circuit uses a core and yoke. Most cores used are stacks ofmagnetic steel sheet. For bundling the stacked core, calking, welding,bolting, etc. are frequently used. With calking and welding, electricalshort-circuits occur between the stacked layers. With AC excitation, ashort-circuiting current is produced and a drop in the performance-ofthe apparatus is caused. Therefore, sometimes molding or bonding is usedfor the bundling between magnetic steel sheets. With molding or bonding,however, use at a high temperature is not possible.

In a heater, the heating element is fastened and insulated by a ceramicor other member able to breakdown a high temperature. This fastening ispartial. Time and labor are required for the assembly process andsometimes noise and vibration become problems due to the partialfastening. With bonding etc., complete fastening is possible. Ifinsulation could be secured, the process would become simple andautomation would also become possible, but at the present time, there isno method of bonding able to be used at a high temperature.

DISCLOSURE OF INVENTION

An object of the present invention is to provide an extremely fast andeasy coating for covering end faces as new technology for treating theend faces of a core to give an insulating coating taking the place ofconventional varnishing, bluing, and other heat treatment due to thefact there are many problems in the adhesiveness, insulation, corrosionresistance, heat resistance, and work efficiency of an insulationcoating after baking in conventional treatment to give an insulationcoating based on bluing and varnishing to improve the corrosionresistance and insulation of end faces of cores.

Another object of the present invention is to provide an electricalapparatus and method of production of the same enabling operation at ahigh temperature.

Still another object of the present invention is to provide a member foran electrical apparatus suppressed in electrical short-circuits andstress and strain accompanying bundling and improved in surface and asimple method of bundling for the same.

(1) A core having a superior end face insulation characterized in thatend faces of the core are treated to give an insulation coating of anaverage film thickness of at least 0.5 μm comprised of at least 30 wt %of a silicone compound converted to SiO₂.

(2) A core having a superior end face insulation as set forth in (1),characterized in that an average film thickness of said insulatingcoating is at least 2 μm and a breakdown voltage is at least 30V.

(3) A core having a superior end face insulation as set forth in (1) or(2), characterized in that said insulating coating has a heat resistancein air of at least 400° C.×1 hour.

(4) A core having a superior end face insulation as set forth in any oneof (1) to (3), characterized in that said silicone compound is a driedcoating comprised of one or more types of a silicone resin, alkalisilicate, colloidal silica, low melting point glass frit, a puresilicone polymer comprised of a compound produced by a hydrolysisreaction and dehydration condensation reaction of one or more types ofsubstances expressed by (R¹)_(n)Si (X¹)_(4-n) (where n is an integer of0 to 3, R¹ is an alkyl group or phenyl group, the plurality of R¹ ableto be different when n=2 or 3, X¹ being Cl (chlorine) or an alkoxy groupexpressed by (OR²), where R² is an alkyl group, and the plurality of R²able to be different when n=O, 1, or 2), a modified silicone polymercomprised of a compound produced by a hydrolysis reaction anddehydration condensation reaction of one or more types of substancesexpressed by (R³)_(n)Si(X²)_(4-n) (where n is an integer of 0 to 3, R³is an organic functional group other than an alkyl group or phenylgroup, the plurality of R³ able to be different when n=2 or 3, X² beingCl (chlorine) or an alkoxy group expressed by (OR⁴), where R⁴ is analkyl group, and the plurality of R⁴ able to be different when n=0, 1,or 2), and a mixed silicon polymer produced by a hydrolysis reaction anddehydration condensation of one or more types of compounds expressed by(R¹)_(n)Si(X¹)_(4-n) (where n is an integer of 0 to 3, R¹ is an alkylgroup or phenyl group, the plurality of R¹ able to be different when n=2or 3, X¹ being Cl (chlorine) or an alkoxy group expressed by (OR²),where R² is an alkyl group, and the plurality of R² able to be differentwhen n=0, 1, or 2) and one or more types of substances expressed by(R³)_(n)Si(X²)_(4-n) (where n is an integer of 0 to 3, R³ an organicfunctional group other than an alkyl group or phenyl group, theplurality of R³ able to be different when n=2 or 3, X² being Cl(chlorine) or an alkoxy group expressed by (OR⁴), where R⁴ is an alkylgroup, and the plurality of R⁴ able to be different when n=0, 1, or 2).

(5) A core having a superior end face insulation as set forth in (4),characterized in that said pure silicone polymer is a compound where thenumber of carbon atoms in the R¹ and R² alkyl groups is not more than 4and produced by a hydrolysis reaction and partial dehydrationcondensation reaction of one or more substances selected fromtetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane,tetrabutoxysilane, monomethyltrimethoxysilane,monomethyltriethoxysilane, monomethyltriisopropoxysilane,monomethyltributoxysilane, monoethyltrimethoxysilane,monoethyltriethoxysilane, monoethyltriisopropoxysilane,monoethyltributoxy-silane, dimethyldimethoxysilane,dimethyldiethoxy-silane, diethyldimethoxysilane, diethyldietoxysilane,phenyltrimethoxysilane, diphenyldimethoxysilane, phenyltriethoxysilane,and diphenyldiethoxysilane and said modified silicone polymer is one ormore of an acryl-modified silicone polymer, alkyd-modified siliconepolymer, polyester acryl-modified silicone polymer, epoxy-modifiedsilicone polymer, amino-modified silicone polymer, vinyl-modifiedsilicone polymer, and fluorine-modified silicone polymer.

(6) A core having a superior end face insulation as set forth in any oneof (1) to (5), characterized in that the metal element or semimetalelement M in said insulation coating other than oxygen (O), carbon (C),hydrogen (H), nitrogen (N), sulfur (S), and fluorine (F) is mainlysilicon (Si) and said Si is mainly present in a form having an Si—O bondand that said M other than Si is one or more elements selected from Li,Na, K, Mg, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y Ti, Zr, Nb, B, Al, Ge, Sn,P, Sb, and Bi.

(7) A core having a superior end face insulation as set forth in any oneof (1) to (6), characterized in that the total weight ratio of Si, Li,Na, K, Mg, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Ti, Zr, Nb, B, Al, Ge, Sn,P, Sb, and Bi with respect to the total weight of elements in saidinsulation coating other than oxygen (O), carbon (C), hydrogen (H),nitrogen (N), sulfur (S), and fluorine (F) is at least 90 parts byweight and in that the weight ratio of Si with respect to the totalweight of elements in said insulation coating other than O, C, H, N, andS is at least 50 parts by weight.

(8) A core having a superior end face insulation as set forth in any oneof (1) to (7), characterized in that the body of said core is comprisedof non-oriented magnetic steel sheet.

(9) A transformer core extremely superior in insulation and corrosionresistance characterized by having an insulation coating comprised of apure silicone polymer on end faces and surfaces of stacked steel sheetsof a magnetic material.

(10) A transformer core extremely superior in insulation and corrosionresistance characterized by having conductors at a core comprised ofstacked magnetic materials and having an insulation coating comprised ofa pure silicone polymer on the surfaces of and between the magneticmaterials and conductors.

(11) A transformer core extremely superior in insulation and corrosionresistance as set forth in (9) or (10), characterized in that theinsulation coating has an average film thickness of 0.5 to 100 μm and abreakdown voltage of at least 30V.

(12) A magnetic member for an electromagnetic apparatus comprised of aplurality of pieces of a magnetic material punched into substantiallythe same shapes stacked and joined together by a silicone polymer, saidmagnetic member for an electromagnetic apparatus characterized by beingjoined without local application of strain and/or stress to the piecesof the magnetic material.

(13) A magnetic member for an electromagnetic apparatus as set forth in(12), wherein an armature core is comprised of a plurality of dividedcore pieces.

(14) A high temperature operating electrical apparatus characterized byhaving conductors or conductors and magnetic materials joined togetherwhile securing electrical insulation between adjoining members of thesame or different type using as a solution exhibiting the ability tomutually fasten and hold adjoining members after being coated and driedbetween adjoining members and having the ability to fasten and bundleeven at a high temperature of over 200° C. a pure silicone polymercomprised of a compound produced by a hydrolysis and partial dehydrationcondensation reaction of one or more pure silicone polymer expressed by(R¹)_(n)Si(X¹)_(4-n) (where n is an integer of 0 to 3, R¹ is an alkylgroup or phenyl group, the plurality of R¹ able to be different when n=2or 3, X¹ being Cl (chlorine) or an alkoxy group expressed by (OR²),where R² is an alkyl group, and the plurality of R² able to be differentwhen n=0, 1, or 2).

(15) A method of processing a core and treating end faces of the core togive an insulation coating comprising, when producing the core, punchingor cutting a material to predetermined shapes, stacking and clampingthem, annealing or not annealing them, treating the end faces of thecore to give an insulation coating, and drying and/or baking the same,said method of treating end faces of a core to give an insulationcoating characterized by using as an insulating coating treatment agentone or more types of a silicone resin, alkali silicate, colloidalsilica, low melting point glass frit, a pure silicone polymer solcomprised of a solution including a compound produced by a hydrolysisreaction and dehydration condensation reaction of one or more types ofsubstances expressed by (R¹)_(n)Si(X¹)_(4-n) (where n is an integer of 0to 3, R¹ is an alkyl group or phenyl group, the plurality of R¹ able tobe different when n=2 or 3, X¹ being an alkoxy group expressed by Cl orO(R²), where R² is an alkyl group, and the plurality of R² able to bedifferent when n=0, 1, or 2), a modified silicone polymer sol comprisedof a solution including a compound produced by a hydrolysis reaction anddehydration condensation reaction of one or more types of substancesexpressed by (R³)_(n)Si(x²)_(4-n) (where n is an integer of 0 to 3, R³is an organic functional group other than an alkyl group or phenylgroup, the plurality of R³ able to be different when n=2 or 3, X² beingan alkoxy group expressed by Cl or O(R⁴), where R⁴ is an alkyl group,and the plurality of R⁴ able to be different when n=0, 1, or 2), and amixed silicone polymer sol comprised of a solution including a compoundproduced by a hydrolysis reaction and dehydration condensation reactionof one or more types of compounds expressed by (R¹)_(n)Si(X¹)_(4-n)(where n is an integer of 0 to 3, R¹ is an alkyl group or phenyl group,the plurality of R¹ able to be different when n=2 or 3, X¹ being analkoxy group expressed by Cl or O(R²), where R² is an alkyl group, andthe plurality of R² able to be different when n=0, 1, or 2) and one ormore types of substances expressed by (R³)_(n)Si(x²)_(4-n) (where n isan integer of 0 to 3, R³ is an organic functional group other than analkyl group or phenyl group, the plurality of R³ able to be differentwhen n=2 or 3, X² being an alkoxy group expressed by Cl or O(R⁴), whereR⁴ is an alkyl group, and the plurality of R⁴ able to be different whenn=0, 1, or 2) for dipping and or spraying and/or brushing to obtain anaverage film thickness after drying and/or baking of 0.5 to 20 μm.

(16) A method of treating end faces of a core to give an insulationcoating as set forth in (15), characterized in that said pure siliconepolymer sol is a compound where the number of carbon atoms in the R¹ andR² alkyl group is not more than 4 including a compound produced by ahydrolysis reaction and partial dehydration condensation reaction of oneor more substances selected from tetramethoxysilane, tetraethoxysilane,tetraisopropoxysilane, tetrabutoxysilane, monomethyltrimethoxysilane,monomethyltriethoxysilane, monomethyltriisopropoxysilane,monomethyltributoxysilane, monoethyltrimethoxysilane,monoethyltriethoxysilane, monoethyltriisopropoxysilane,monoethyltributoxysilane, dimethyldimethoxysilane,dimethyldiethoxysilane, diethyldimethoxysilane, diethyldietoxysilane,phenyltrimethoxysilane, diphenyldimethoxysilane, phenyltriethoxysilane,and diphenyldiethoxysilane and in that said modified silicone polymersol is a solution including one or more of an acryl-modified siliconepolymer, alkyd-modified silicone polymer, polyester acryl-modifiedsilicone polymer, epoxy-modified silicone polymer, amino-modifiedsilicone polymer, vinyl-modified silicone polymer, and fluorine-modifiedsilicone polymer.

(17) A method of treating end faces of a core to give an insulationcoating as set forth in (15) or (16), characterized in that the metalelement or semimetal element M in said insulation coating other thanoxygen (O), carbon (C), hydrogen (H), nitrogen (N), sulfur (S), andfluorine (F) is mainly silicon (Si) and said Si is mainly present in aform having an Si—O bond and that said M other than Si is one or moreelements selected from Li, Na, K, Mg, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, YTi, Zr, Nb, B, Al, Ge, Sn, P, Sb, and Bi.

(18) A method of treating end faces of a core to give an insulationcoating as set forth in any one of (15) to (17), characterized in thatthe total weight ratio of Si, Li, Na, K, Mg, Ca, Cr, Mn, Fe, Co, Ni, Cu,Zn, Y, Ti, Zr, Nb, B, Al, Ge, Sn, P, Sb, and Bi with respect to thetotal weight of elements in said insulation coating other than oxygen(O), carbon (C), hydrogen (H), nitrogen (N), sulfur(S), and fluorine (F)is at least 90% and in that the weight ratio of Si with respect to thetotal weight of elements in said insulation coating other than O, C, H,N, and S is at least 50 wt %.

(19) A method of treating end faces of a core to give an insulationcoating as set forth in any one of (15) to (18), characterized byfurther adding to said insulation coating treatment agent as a filler0.1 to 50 parts by weight as solid content of one or more of inorganicoxide powder particles, an inorganic oxide colloidal substance, organicresin powder particles, and an organic resin emulsion solution withrespect to 100 parts by weight worth of SiO₂ of pure silicone polymersol, modified silicone polymer sol, and/or mixed silicone polymer sol.

(20) A method of treating end faces of a core to give an insulationcoating as set forth in (19), characterized by using as said inorganicpowder particles or colloidal substance one or more of SiO₂, Al₂O₃,TiO₂, ZrO₂, and/or composites of the same having a primary particle sizeof 7 to 5000 nm.

(21) A method of treating end faces of a core to give an insulationcoating as set forth in (19), characterized by using as said organicresin powder particles or emulsion solution substance one or moresubstances selected from acryl, polystyrene, polyethylene,polypropylene, polyamide, polycarbonate, polyurethane, melamine, phenol,epoxy resin, and/or copolymers of the same having a particle size of 50to 10,000 nm.

(22) A method of treating end faces of a core to give an insulationcoating as set forth in any one of (15) to (21), characterized by, whentreating the end faces of the core, treating them with at least tworepeated coatings interspersed with drying at room temperature to 300°C. for at least 30 seconds.

(23) A method of treating end faces of a core to give an insulationcoating as set forth in any one of (15) to (22), characterized by, whengiving repeated coatings, coating an insulating coating agent to whichthe filler set forth in any one of (19) to (20) is added and blended byat least one coating treatment to obtain a thickness after drying of thelayer including said filler of 0.2 to 10 μm and coating an insulationcoating agent to which a filler is not added and blended in at least thefinal coating treatment to obtain an average film thickness of the totalinsulation coating agent of 0.5 to 20 μm.

(24) A method of treating end faces of a core to give an insulationcoating as set forth in any one of (15) to (23), characterized in thatsaid core is comprised of; non-oriented magnetic steel sheet.

(25) A method of production of a transformer core extremely superior ininsulation and corrosion resistance characterized by coating the endfaces or surface of a transformer core comprised of a stack of magneticmaterials with a pure silicone polymer and drying it to form aninsulation coating.

(26) A method of production of a transformer core extremely superior ininsulation and corrosion resistance characterized by stacking magneticmaterials, attaching conductors, then coating an insulation coating ofan organic silicon compound and drying it to fasten the magneticmaterials and conductors.

(27) A method of production of a transformer core extremely superior ininsulation and corrosion resistance as set forth in (25) to (26),characterized in that the coated and dried insulation coating has anaverage film thickness of 2 to 100 μm and a breakdown voltage of atleast 30V.

(28) A method of production of a transformer core extremely superior ininsulation and corrosion resistance as set forth in any one of (25) to(27), characterized by using as the pure silicone polymer a heat curingtype compound.

(29) A method of production of a transformer core extremely superior ininsulation and corrosion resistance as set forth in any one of (25) to(28), characterized by performing the coating and drying treatment oneor more times by at least one method of dipping, spraying, and brushingusing as the pure silicone polymer one or more types of treatment agentsobtained by preparing a silane expressed by the general formulas(R¹)_(n)Si(X¹)_(4-n) (where n is an integer of 0 to 3, R¹ is an alkylgroup or phenyl group, the plurality of R¹ able to be different when n=2or 3, X¹ being Cl (chlorine) or an alkoxy group expressed by (OR²),where R² is an alkyl group, and the plurality of R² able to be differentwhen n=0, 1, or 2).

(30) A method of production of a transformer core extremely superior ininsulation and corrosion resistance as set forth in (29), characterizedin that the pure silicone polymer contains at least 50% of Si(OX¹)₄ andR¹Si(OX²)₃.

(31) A method of production of a transformer core extremely superior ininsulation and corrosion resistance as set forth in any one of (25) to(30), characterized by adding and blending as inorganic powder particlesor a colloidal substance 0.1 to 50 parts by weight of one or more ofSiO₂, Al₂O₃, TiO₂, ZrO₂, and/or composites of the same with respect to100 parts by weight worth of SiO₂ contained in the pure silicone polymeras an additive.

(32) A method of production of a transformer core extremely superior ininsulation and corrosion resistance as set forth in many one of (25) to(31), characterized in that a drying temperature of the pure siliconepolymer is not more than 200° C.

(33) A simple method of bundling magnetic members for an electromagneticapparatus comprised of a plurality of pieces of a magnetic material,said bundling method of a magnetic member for an electromagneticapparatus characterized by arranging and assembling said plurality ofpieces of magnetic material, then coating a solution exhibiting anability for bundling pieces of magnetic material by drying or dippingthem into the solution, then drying to join them together.

(34) A simple bundling method of a magnetic member for anelectromagnetic apparatus characterized by stacking a plurality ofpieces of magnetic material punched to substantially the same shapes,then coating a solution exhibiting an ability for bundling pieces ofmagnetic material by drying or dipping them into the solution, thendrying to join them together.

(35) A simple bundling method of a magnetic member for anelectromagnetic apparatus as set forth in (33) or (34), characterized byusing as a solution exhibiting the ability to bundle pieces of magneticmaterials together by drying a solution mainly comprised of at least onetype of a pure silicone polymer and modified silicone polymer.

(36) A simple bundling method of a magnetic member for anelectromagnetic apparatus as set forth in any one of (33) to (35),characterized by using as the pure silicone polymer an organic siliconcompound produced by a hydrolysis and partial dehydration condensationreaction of one or more substances expressed by (R¹)_(n)Si(X¹)_(4-n)(where n is an integer of 0 to 3, R¹ is an alkyl group or phenyl group,the plurality of R¹ able to be different when n=2 or 3, X¹ being Cl(chlorine) or an alkoxy group expressed by (OR²) where R² is an alkylgroup, and the plurality of R² able to be different when n=0, 1, or 2).

(37) A simple bundling method of a magnetic member for anelectromagnetic apparatus as set forth in any one of (33) to (35),characterized by using as said modified silicone polymer one or more ofan acryl-modified silicone polymer, alkyd-modified silicone polymer,polyester acryl-modified silicone polymer, epoxy-modified siliconepolymer, amino-modified silicone polymer, vinyl-modified siliconepolymer, and fluorine-modified silicone polymer.

(38) A method of production of a high temperature operating electricalapparatus as set forth in any one of (28) to (42), characterized byusing as a solution exhibiting the ability to mutually fasten and holdadjoining members after being coated and dried between adjoining membersand having the ability to fasten and bundle them even at a hightemperature of over 200° C. a pure silicone polymer comprised of acompound produced by a hydrolysis and partial dehydration condensationreaction of one or more organic silicon compounds expressed by(R¹)_(n)Si(X¹)_(4-n) (where n is an integer of 0 to 3, R¹ is an alkylgroup or phenyl group, the plurality of R¹ able to be different when n=2or 3, X¹ being Cl (chlorine) or an alkoxy group expressed by (OR²),where R² is an alkyl group, and the plurality of R² able to be differentwhen n=0, 1, or 2), coating said solution on conductors or conductorsand magnetic materials or dipping the conductors or conductors andmagnetic materials in said solution, then drying to join together theconductors or conductors and magnetic materials while securingelectrical insulation between adjoining members of the same or differenttype.

(39) A method of production of a high temperature operating electricalapparatus as set forth in (38), characterized by using a pure siliconepolymer comprised of an organic silicon compound expressed by(R¹)_(n)Si(X¹)_(4-n) (where n is an integer of 0 to 3, R¹ is an alkylgroup or phenyl group, the plurality of R¹ able to be different when n=2or 3, X¹ being Cl (chlorine) or an alkoxy group expressed by (OR²),where R² is an alkyl group, and the plurality of R² able to be differentwhen n=0, 1, or 2), containing at least a 80% of at least an n=0, 1organic silicon compound and having a ratio of composition of an organicsilicon compound of n=0 and an organic silicon compound of n=1 of 1:20to 4:1.

(40) A method of production of a high temperature operating electricalapparatus as set forth in any one of (38) or (39), characterized byusing as a pure silicone polymer (compound) a heat curing type puresilicone polymer.

(41) A method of production of a high temperature operating electricalapparatus as set forth in any one of (38) to (40), characterized byadding as an additive to the pure silicone polymer 0.1 to 10 parts byweight of one or more of SiO₂, Al₂O₃, and TiO₂ having a primary particlesize of 7 to 5,000 nm.

(42) A method of production of a high temperature operating electricalapparatus as set forth in any one of (38) to (41), characterized in thatthe thickness after drying is 2 to 100 μm.

(43) A method of production of a high temperature operating electricalapparatus as set forth in any one of (38) to (42), characterized in thatthe drying temperature is not more than 200° C.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a view of the relationship between the film thickness andbreakdown voltage in the case of baking while changing the thickness ofdeposition after drying for the solution of Invention Example 3 andInvention Example 6 in Example 1;

FIG. 2 is a view of a divided core piece;

FIG. 3 is a view of the state of the stacked divided core pieces heldand fastened;

FIG. 4 is a partial detailed view of stacked divided core pieces formedwith a bundling film;

FIG. 5 is a perspective view of stacked divided core pieces providingwith a winding on a bundling film;

FIG. 6 is a view of the state of stacked divided core pieces providedwith a winding dipped in a bundling solution;

FIG. 7 is a view of the state of stacked divided core pieces bundled ina case;

FIG. 8 is a sectional view (a) and plan view (b) of an IPM rotor; and

FIG. 9 is a sectional view of a reactor formed with a bundling film.

BEST MODE FOR CARRYING OUT THE INVENTION

The core in the present invention is a core of a motor, actuator,generator, transformer, reactor, or other energy converting device, thatis, a stacked core (including wire type, rod type, block type, and othercores, molded powder cores, etc.) of magnetic steel sheet (includingstainless steel sheet and iron sheet used as magnetic materials).

Parts of the processed end faces and surfaces of cores are either notprovided with any insulation coatings or else not provided with muchcoatings at all. In cores with no insulation or poor insulation on theend faces or surfaces of the cores, sometimes the members contacting thecores such as the secondary conductors of induction machines, casesfastening the cores in motors, generators, etc., bolts and otherfastening members, windings, and magnets short-circuit with the coresand cause an increase in loss due to the short-circuiting current and areduction in the torque, thrust, or output.

Further, when the end faces or surfaces of the cores have a lowcorrosion resistance, the end faces or surfaces easily rust. This rustdamages the media and encoders and other precision sensors of recordingapparatuses or cause various mechanical problems, so improvement of thecorrosion resistance is important.

In the past, as measures for improving the insulation and corrosionresistance of the end faces and surfaces of cores in formation of coresusing magnetic steel sheet, after punching a loop material into a core,varnishing, painting, bluing, or other heat treatment is employed.

In the prior art, however, at the time of varnishing, as pre-treatment,cleaning, annealing, etc. are necessary for removing the punching oildeposited at the time of punching and there were problems in facilities,time, and cost. Further, the bonding force, insulation, and corrosionresistance of the varnish formed were unstable and a sufficient effecthard to obtain, so at the time of varnishing, there was the problem thatit was impossible to obtain the necessary thick coating or more.

Further, even with bluing, in addition to the problems of the time andcost taken for annealing, there were problems in the stability andcorrosion resistance of the oxide film and in the insulation effect.

The inventors tackled the improvement of the insulation coating fordifferent compositions of solutions, coating conditions, and drying orbaking conditions. As a result, they discovered that a core having anextremely superior insulation could be obtained by using a solutioncomprised mainly of a silicon compound as the end face treatment agent.

A coating comprised of at least 30 parts by weight of converted SiO₂ issuperior in insulation. In particular, the inventors succeeded indevelopment of a core end face coating and a coating method resulting insuperior appearance, adhesiveness, heat resistance, corrosionresistance, abrasion resistance, and insulation in a short time withoutrequiring pre-treatment or high temperature drying etc. by an insulationcoating comprised of a pure silicone polymer, modified silicone polymer,and/or mixed silicone polymer formed by dipping or spraying a sol mainlycomprised of an organic silicon compound.

Here, “weight of converted SiO₂” indicates the case of making all Sipresent in the form of siloxane (Si—O—Si) bonds in the silicon compoundthe form of SiO₂.

Further, “purified silicone polymer” means a compound produced by ahydrolysis reaction and dehydration condensation reaction of one or moretypes of substances expressed by (R¹)_(n)Si(X¹)_(4-n) (where n is aninteger of 0 to 3, R¹ is an alkyl group or phenyl group, the pluralityof R¹ able to be different when n=2 or 3, X¹ being Cl (chlorine) or analkoxy group expressed by (OR²), where R² is an alkyl group, and theplurality of R² able to be different when n=0, 1, or 2), a “modifiedsilicone polymer” means a compound produced by a hydrolysis reaction anddehydration condensation reaction of one or more types of substancesexpressed by (R³)_(n)Si(X¹)_(4-n) (where n is an integer of 0 to 3, R³is an organic functional group other than an alkyl group or phenylgroup, the plurality of R³ able to be different when n=2 or 3, X² beingCl (chlorine or an alkoxy group expressed by (OR⁴), where R⁴ is an alkylgroup, and the plurality of R⁴ able to be different when n=0, 1 or 2),and a “mixed silicone polymer” means a compound produced by a hydrolysisreaction and dehydration condensation reaction of one or more types ofcompounds expressed by (R¹)_(n)Si (X¹)_(4-n) (where n is an integer of 0to 3, R¹ is an alkyl group or phenyl group, the plurality of R¹ able tobe different when n=2 or 3, X¹ being Cl (chlorine) or an alkoxy groupexpressed by (OR²) where R² is an alkyl group, and the plurality of R²able to be different when n=0, 1, or 2), and one or more types ofsubstances expressed by (R³)_(n)Si(X²)_(4-n) (where n is an integer of 0to 3, R³ is an organic functional group other than an alkyl group orphenyl group, the plurality of R³ able to be different when n=2 or 3, X²being Cl (chlorine) or an alkoxy group expressed by (OR⁴), where R⁴ isan alkyl group, and the plurality of R⁴ able to be different when n=0,1, or 2).

Further, the solution states of these silicone polymers are made puresilicone polymers, modified silicone polymers, and mixedsilicone-polymers.

The present invention will be explained in detail below.

The present invention is characterized by a method of treatment forgiving an insulation coating to core end faces. The composition of thesolution is characterized by the use of one or more types of a siliconeresin, alkali silicate, colloidal silica, low melting point glass frit,a pure silicone polymer sol, a modified silicone polymer sol, and amixed silicone polymer sol as the composition of the solution. Bydipping the core material in such a solution or coating it by spraying,it is possible to form a uniform, dense coating on the exposed surfacesof the iron formed at the time of punching, that is, the core end facesor slot part.

In particular, when the silicone compound used is one or more types of apure silicone polymer sol, modified silicone polymer sol, and mixedsilicone polymer sol, the drying is finished at a low temperature in ashort time and a dense film with good adhesiveness and insulation isformed on the core end faces.

It was learned that a film of in particular a pure silicone polymeramong the silicone polymers formed from these sols gives a more superiorheat resistance and is optimal for the production of a core including anannealing step.

Further, as a method for forming a coating at a lower temperature andshorter time, it is effective to introduce a metal or semimetal otherthan Si having a cross-linking action, that is, Li, Na, K, Mg, Ca, Cr,Mn, Fe, Co, Ni, Cu, Zn, Y, Ti, Zr, Nb, B, Al, Ge, Sn, P, Sb, or Bi inthe form of an alkoxide or chloride dissolved in a solvent and cause adehydration condensation reaction along with a silicone compound andthereby speed up the formation of the siloxane (Si—O—Si) bond network.

When trying to obtain a high insulation resistance or voltageresistance, corrosion resistance, or heat resistance, it is possible toadd 0.1 to 50 parts by weight in terms of solid content of one or moretypes of inorganic oxide powder particles, an inorganic oxide colloidalsubstance, organic resin powder particles, and an organic resin emulsionsolution per 100 parts by weight worth of SiO₂ of all of the siliconepolymer as a filler to a silicone polymer among the above siliconecompounds and thereby obtain an extremely remarkable effect ofimprovement of the insulation and breakdown voltage and, as a compositeeffect, further improve wetability power to the core end faces or steelsheet surface.

In treatment by such a coating agent, pre-treatment such as cleaning orannealing is not necessarily required as in the conventional case ofusing an organic varnish or inorganic insulation agent. There is theadvantage that the punched core material can be directly treated to giveit an insulation coating after clamping.

When coating an insulation agent solution, the ability of the solutionto deposit on the core end faces is controlled by controlling the typeof the solvent and the ratio, concentration, and viscosity of thesolvent. The solution is coated to a predetermined thickness bycontrolling the pullout speed in the case of dipping and the nozzleshape, the ejection speed, etc. in the case of spraying in combinationwith the solution conditions. At this time, when the desired thicknesscannot be obtained by a single treatment, the thickness can be obtainedby coating once, drying at a low temperature, then dipping or sprayingagain.

The drying conditions in the case of the silicone compound of thepresent invention are drying and baking at a low temperature of lessthan 300° C. and a short time.

In particular, when using a pure silicone polymer, modified siliconepolymer, or mixed silicone polymer obtained using silane as a stockmaterial, it is sufficient to dry at room temperature to 120° C. or so.In particular, when using a modified silicone polymer or mixed siliconepolymer, low temperature and short time drying becomes possible by theaction of the modified functional groups. When requiring short timedrying, in the same way as using a silicone compound, extremely fasttreatment of the core end faces becomes possible by drying at atemperature of up to 300° C. or so.

Next, the reasons for the limitations of the present invention will beexplained.

First, the reasons for limitation of the core material having a highinsulation will be explained.

The core of the present invention is characterized by having a coatinghaving an average film thickness of at least 0.5 μm and containing atleast 30 parts by weight of a silicon compound in the coating convertedto SiO₂.

The reason why the average film thickness of the coating of the core endfaces was made at least 0.5 μm is that it is necessary to obtain aneffect of improvement of the insulation and corrosion resistance. Withan average film thickness of less than 0.5 μm, sufficient insulation andcorrosion resistance cannot be obtained if locally thin portions of thecoating occur.

Further, the reason why it is necessary to include at least 30 parts byweight of a silicon compound in the coating as SiO₂ is that this isimportant for the density, insulation, and heat resistance of thecoating. In particular, it is preferable to include it in an amount ofat least 50 parts by weight, more preferably at least 75 parts byweight, to improve the insulation and the heat resistance.

Another characteristic is that the silicon compound is comprised of oneor more types of an alkali silicate, colloidal silica, low melting pointglass frit, pure silicone polymer, modified silicone polymer, and mixedsilicone polymer.

When treating surfaces by these silicon compounds and drying them, theinsulation coating is dense and a uniform coating is formed. The alkalisilicate used is one or more types of compounds expressed byM₂O.nSiO₂.mH₂O (M: LiNa, K, n: 1 to 4) such as sodium silicate.

A core having an organic silicon compound coating called, in particular,a pure silicone polymer, modified silicone polymer, or mixed siliconepolymer among these silicone compounds, features a dense coating withabundant uniformity and giving superior performance in corrosionresistance and insulation. In particular, in the case of a core having apure silicone polymer coating, there is the advantage of superior heatresistance at a higher temperature.

As the most preferable insulation coating condition, there is aninsulation coating comprised of a dry film of a pure silicone polymer,modified silicone polymer, and/or mixed silicone polymer among the abovesilicone compounds, having an average thickness of at least 2.0 μm,preferably 2.5 to 20 μm on the core end faces, and having a breakdownvoltage of at least 30V.

A core changes in the shape and roughness of its end faces depending onthe conditions of the cutting or punching of the material. If at least2.0 μm in thickness, any variation is absorbed and stable insulation isobtained. If the thickness is too thick, cost problems or problems suchas reduction of the adhesiveness of the insulation coating arise.

Another feature of the core of the present invention is that the heatresistance is at least 400° C. The “heat resistance” referred to in thepresent invention means the adhesiveness and insulation properties notbeing impaired when annealing at that temperature when using inparticular a pure silicone polymer sol among the treatment agents usedin the present invention, the heat resistance is superior. This makes itsuitable at the time of Al diecasting or Cu diecasting of the core.

Further, in the case of this silicone polymer sol, a heat curing type ofsilicone polymer sol is a more preferable treatment agent. This isbecause in the case of a heat curing type, there is the advantage thatthe solution seeping between the steel sheets in the dipping or othercoating process can be dried in a short time at the time of heating anddrying.

The inventors investigated the insulation of motor cores and theefficiency of cores and discovered that by improvement of the insulationof the core end faces had the effect of improvement of the electricalinsulation with the members contacting a core, suppressed theshort-circuiting current between sheets causing an increase in loss anddrop in output, and increased the motor torque (thrust) and output.

For example, in a high speed induction motor (180,000 rpm, two poles),with a secondary conductor interval in the rotating core of 2 cm, a coreheight (stacked height of magnetic steel sheets) of 50 cm, and coreexcitation magnetic flux of 1 T, a breakdown voltage of at least 34V(reference: 180,000 rpm/60 s=3 kHz, √2ô×3,000×0.02 m×0.5 m/2×1 T× twoend faces=33.3V) becomes necessary. Therefore, in practice, at least 50Vbecomes necessary.

The coating obtained by the pure silicone polymer, modified siliconpolymer, and mixed silicone polymer of the present invention forms adense insulation coating of a superior adhesiveness comprised mainly ofSiO₂ by curing in a layer shape or three-dimensional shape by lowtemperature drying in a short time in the process of removal of thealcohol or other solvent contained in the solution.

Since a breakdown voltage of at least 30V is obtained if making the filmthickness after drying at least 0.5 μm by the insulation coating formedin this way, the lower limit of the average film thickness is made 0.5μm.

If the film thickness is more than 20 μm, however, depending on thedrying or baking conditions, the adhesiveness of the coating after thetreatment falls, cracks occur. In particular, when subjected to heattreatment, bonding defects sometimes occur. Further, a long time istaken for drying, which leads to cost increases, so the thickness islimited.

The insulation coating used is one or more types of a pure siliconepolymer, modified silicone polymer, or mixed silicone polymer. The puresilicone polymer sol is produced, for example, by hydrolysis reactionand partial dehydration condensation without a solvent or in aninorganic solvent of one or more types of substances expressed by(R¹)_(n)Si(X¹)_(4-n) (where n is an integer of 0 to 3, R¹ is an alkylgroup or phenyl group, the plurality of R¹ able to be different when n=2or 3, X¹ being an alkoxy group expressed by Cl or O(R²), where R² is analkyl group, and the plurality of R² able to be different when n=0, 1,or 2).

At this time, it is possible to change the type of the stock silanemonomer used so as to impart various types of performance to a coatingformed from the sol.

Further, the inventors used pure silicone polymer for repeated massiveexperiments and studies on the conditions for obtaining a thick filmwith good insulation and heat resistance and as a result found out thatuse of a so-called four-function or three-function silicone polymer ofthe composition of the above general formula where n=0 or 1 isoverwhelmingly advantageous when a heat treatment step is included.

In particular, by combining the n=1 component in a range of 20 to 80% inthe combination of n=0 and 1, a thick insulation coating extremelysuperior in appearance, insulation, heat resistance, and adhesivenessbecomes possible.

A modified silicone polymer is a stock monomer of a pure siliconepolymer modified by an organic resin other than an alkyl group or phenylgroup. As the method of modification, the polymer is modified by a knowncold blend or condensation reaction etc.

A mixed silicone polymer is produced by hydrolysis and dehydrationcondensation of a stock monomer forming a pure silicone polymer and astock monomer forming a modified silicone polymer in desiredproportions. The pure silicone polymer component and the modifiedsilicone polymer component are networked at the molecular level.

The stock material of the sol for obtaining a pure silicone polymer usedis one or more types of C4 or less alkyl group tetramethoxysilane,tetraethoxy-silane, tetraisopropoxysilane, tetrabutoxysilane,monomethyltrimethoxysilane, monomethyltriethoxysilane,monomethyltriiso-propoxysilane, monomethyltributoxysilane,monoethyltrimethoxysilane, monoethyltriethoxysilane,monoethyltriisopropoxysilane, monoethyltributoxysilane,dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane,diethyldietoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane,phenyltriethoxysilane, and diphenyldiethoxysilane and further silanetetrachloride, titanium methyl trichloride, etc. as silane chlorides.

The introduction of the alkyl group or phenyl group enables flexibilityand processability to be imparted to the coating and enables a betterheat resistance to be exhibited compared with other organic functionalgroups.

However, along with an increase in the number of carbon atoms of thealkyl group, the heat resistance falls, the film-formability falls, thedrying temperature becomes higher, and other problems arise, so not morethan four carbon atoms is desirable. In particular, when consideringheat resistance of 500 to 600° C. or so, not more than one carbon atomis desirable.

As the modified silicone polymer, for example, use is made of one ormore of an acryl-modified silicone polymer, alkyd-modified siliconepolymer, polyester acryl-modified silicone polymer, epoxy-modifiedsilicone polymer, amino-modified silicone polymer, vinyl-modifiedsilicone polymer, and fluorine-modified silicone polymer. These modifiedsilicone polymers give rise to bonds between organic functional groupsother than Si—O—Si bonds as well, so a dense insulation coating isobtained at a low temperature.

The mixed silicone polymer is formed by using one or more of each of astock monomer for obtaining the above pure silicone polymer and stockmonomer of a modified silicone polymer. This polymer enables achievementof both of the heat resistance etc. of a pure silicone polymer and thelow temperature curability, water repellency, and other functions of amodified silicone polymer at the molecular level.

Further, it is possible to introduce to any of these silicone polymersanother metal oxide as the catalyst or cross-linking point for promotingthe condensation reaction. As metal alkoxides of the stock material atthis time, there are titanium tetraethoxide, titanium isopropoxide,aluminum butoxide, etc.

An insulation coating comprised of such silicone polymers forms a dense,strong coating mainly comprised of SiO₂ by an extremely fast drying stepwhere desolvation and dehydration occur simultaneously. Therefore, theinsulation coating formed is dense and has corrosion-resistance and isresistant to compression stress. This is advantageous when performingvarious processing in later steps.

Further, when the organic group is an alkyl group such as a methylgroup, a phenyl group, or a group including fluorine such as a CH₃group, there is water repellency and a more superior corrosionresistance is obtained, so this contributes to improvement of thecorrosion resistance.

Each of these silicone polymers gives a better coating than the priorart, but in the case of a pure silicone polymer, a more dense coatingwith a good insulation, heat resistance, and adhesiveness is obtained,while in the case of a modified silicone polymer or mixed siliconepolymer, a slightly inferior tendency is exhibited compared with theformer case in insulation, film strength, corrosion resistance, heatresistance, etc. due to the organic resin component contained.

Further, the advantage in the case where the metal element or semimetalelement M other than oxygen, carbon, hydrogen, and nitrogen is mainlysilicon (Si), said Si is mainly present in a form having an Si—O bond,and said M other than silicon contains one or more elements selectedfrom Li, Na, K, Mg, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y Ti, Zr, Nb, B, Al,Ge, Sn, P, Sb, and Bi as preferable conditions for the above insulationcoating are due to the following:

To impart insulation, the insulation coating is preferably a denseamorphous structure. Therefore, it is necessary to make an Si—O—Sinetwork structure having an amorphous structure up to a relatively hightemperature the basic skeleton of the coating matrix.

In the method of forming a coating from a solution (sol), however, thereis a problem of peeling of the coating due to shrinkage occurring at thetime of desolvation or condensation.

As a measure to solve this, there is the method of dispersing a stableoxide in a solvent and introducing it into the coating. There is anadvantage to addition of an oxide or composite oxide of a metal orsemimetal other than Si suitable for the solvent.

Further, a condensation reaction of Si—O—Si has the defect of agenerally low reactivity. To improve this reactivity, a metal orsemimetal catalyst is added or M-O bonds of a metal or semimetal (M)other than Si forming a cross-linking point of an Si—O—Si network areintroduced by using an alkoxide or acetyl acetate complex or chloride ofM. A dense film including M is formed in a short time. As a result, thecoating including M gives a dense insulation coating with few cracks.

Next, the reason for making the total weight ratio of Si, Li, Na, K, Mg,Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Ti, Zr, Nb, B, Al, Ge, Sn, P, Sb, andBi in the insulation coating with respect to the total weight ofelements in said insulation coating other than oxygen, carbon, hydrogen,nitrogen, sulfur, and fluorine at least 90 parts by weight and makingthe weight ratio of Si with respect to the total weight of elements insaid insulation coating other than oxygen, carbon, hydrogen, nitrogen,sulfur, and fluorine at least 50 parts by weight is as follows:

A high insulation is basically held by the insulating oxide in thecoating. Therefore, the ratio of the component metal of the insulatingoxide, that is, Si, Li, Na, K, Mg, Ca, Y, Ti, Zr, Nb, B, Al, Ge, Sn, P,Sb, and Bi, is preferably at least 90 parts by weight, more preferablyat least 95 parts by weight, in all components other than the oxygen,carbon, hydrogen, nitrogen, sulfur, and fluorine contained in theorganic functional group introduced for the purpose of impartingprocessability, water repellency, etc. and further other than the oxygenfor limiting the metal component.

Among these, as mentioned above, the matrix structure of the coatingcontributes greatly to the Si—O—Si network. In the insulation coating,the weight ratio of the basic skeletal component, that is, Si, has to beat least 50 parts of the total weight of the elements other than oxygen,carbon, hydrogen, nitrogen, sulfur, and fluorine and preferably is atleast 75 parts by weight from the viewpoint of the improvement of theinsulation and the improvement of the coating strength.

In applying the present invention, it is advantageous to use as the corematerial in particular a non-oriented magnetic steel sheet and use itfor insulation of the end faces at the time of assembly of the core.That is, in the core material of a motor core etc., in almost all cases,the stacked core is treated to prevent rust or is either or bothannealed or treated with an organic varnish for insulation. The effectsof this are tremendous.

Next, in the method of production of a core using the present invention,in the step of processing the core, the non-oriented magnetic steelsheet core is punched, stacked, clamped, and, in accordance with need,treated to prevent rust or for insulation etc. The technology of thepresent invention enables a simple, low cost, and high productivitynon-oriented magnetic steel sheet core having a superior coatingperformance to be easily obtained.

As the silicone compound used as a component of the insulation coatingagent, the core is treated by one or more of a silicone resin, alkalisilicate, colloidal silica, low melting point glass frit, pure siliconepolymer sol, modified silicone polymer sol, and mixed silicone polymersol.

The core is characterized by being produced to give an average thicknessof the insulation coating of 0.5 μm to 20 μm. When treating it by such asilicon compound and drying it, the insulation coating is formed denseand uniform as a coating.

In particular, when using a pure silicone polymer sol, modified siliconepolymer sol, and mixed silicone polymer sol comprised of an organicsilicon compound, no cleaning, annealing, or other pre-treatment isneeded in the treatment by the insulation coating agent, so this iseffective in reduction of the cost of industrial treatment.

Further, the insulation coating is dense and uniform and superior incorrosion resistance and insulation. Further, in the case of a puresilicone polymer, there is the advantage of superiority in heatresistance at a higher temperature. This is advantageous in the case ofincluding an annealing, aluminum diecasting, or other heat treatmentstep.

In the case of such a coating of the present invention, when the averagefilm thickness is less than 0.5 μm, a sufficient effect of improvementof the insulation and corrosion resistance cannot be obtained. On theother hand, with a film thickness of more than 20 μm, locally thickportions occur and the stacked thickness of the core increases or theadhesiveness deteriorates. In particular, this is set as a limit sincewhen including an annealing step, local peeling or detachment of theinsulation coating easily occurs.

For coating these, there are the methods of dipping, spraying, etc., butdipping is advantageous if considering the simplicity of the facilitiesand efficiency of use of the solution.

The coating agent characterizing the present invention features, interms of the composition of the solution, the use of one or more of apure silicone polymer sol, modified silicone polymer sol, and mixedsilicone polymer sol.

A pure silicone polymer sol is produced by hydrolysis and partialdehydration condensation without a solvent or in an organic solvent ofone or more types of known substances expressed by (R¹)_(n)Si(X¹)_(4-n)(where n is an integer of 0 to 3, R¹ is an alkyl group or phenyl group,the plurality of R¹ able to be different when n=2 or 3, X¹ being analkoxy group expressed by Cl or O(R²), where R² is an alkyl group, andthe plurality of R² able to be different when n=0, 1, or 2) and held inthe sol state.

A modified silicone polymer sol is a solution of a compound obtained byhydrolysis and partial dehydration condensation of the stock monomer ofa pure silicone polymer sol modified by an organic resin other than analkyl group or phenyl group. The method of modification is knownmodification by cold blending, a condensation reaction, etc.

A mixed silicone polymer sol is produced by hydrolysis and dehydrationcondensation of a stock monomer forming a pure silicone polymer sol anda stock monomer forming a modified silicone polymer sol in a desiredratio and is structured with the pure silicone polymer sol component andmodified silicone polymer sol component networked on the molecularlevel.

Further, these coating agents may be made into sols giving O-M-O—Sibonds by causing hydrolysis and partial dehydration condensation of ametal or semimetal (M) other than Si as an alkoxide or chloride.

The stock material of the pure silicone polymer sol used is one or moreof types of C4 or less alkyl group tetramethoxysilane,tetraethoxysilane, tetraisopropoxysilane, tetrabutoxysilane,monomethyltrimethoxysilane, monomethyltriethoxysilane,monomethyltriisopropoxysilane, monomethyltributoxysilane,monoethyltrimethoxysilane, monoethyltriethoxysilane,monoethyltriisopropoxysilane, monoethyltributoxysilane,dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane,diethyldietoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane,phenyltriethoxysilane, and diphenyldiethoxysilane and further silanetetrachloride, titanium methyl trichloride, etc. as silane chlorides.

The modified silicone polymer sol used is for example one or more of anacryl-modified silicone polymer, alkyd-modified silicone polymer,polyester acryl-modified silicone polymer, epoxy-modified siliconepolymer, amino-modified silicone polymer, vinyl-modified siliconepolymer, and fluorine-modified silicone polymer. These are used suitablydiluted by water and/or alcohol or another solvent.

In particular, a modified silicone polymer having a polar functionalgroup is effective operation wise in that it does not require alcohol asa solvent. Further, with a modified silicone polymer, bonds betweenorganic functional groups other than Si—O—Si bonds occur. This iseffective for forming a dense insulation coating at a low temperature.

As the mixed silicone polymer, one or more of each of a stock monomerfor obtaining the above pure silicone polymer and stock monomer of amodified silicone polymer is used. Further, as the metal alkoxide usedas a cross-linking point of the matrix, there is titanium tetraethoxide,titanium isopropoxide, aluminum butoxide, etc.

The solution for treating the core end faces, surface, etc. with thesesilicone polymers performs desolvation and dehydration simultaneously,so dries extremely fast and forms a dense, coating mainly comprised ofSi—O structure. Further, the insulation coating formed is dense, hascorrosion resistance, and is resistant to compression stress. It isadvantageous when performing various processing in later steps.

When using these silicone polymer sols and the film thickness afterdrying and/or baking is 0.5 to 20 μm, the adhesiveness is excellent andan insulation treatment of core end faces superior in insulation,breakdown voltage, corrosion resistance, and heat resistance can beachieved. In particular, with a pure silicone polymer, an insulationcoating more superior in heat resistance is obtained.

In particular, when using one or more of tetraethoxysilane,tetramethoxysilane, methyltriethoxysilane, methyltrimethoxysilane, etc.,a superior heat resistance is obtained. On the other hand, in the caseof said modified silicone polymer or mixed silicone polymer, there is atendency exhibited for the heat resistance to deteriorate, so this issuited for applications where no annealing is performed.

By adding as a filler to a coating solution using one or more of a puresilicone polymer sol, modified silicone polymer sol, and mixed siliconepolymer sol one or more of inorganic powder particles, organic resinpowder particles, and/or emulsion solutions or colloidal solutions ofthe same in an amount, in solid content, of 0.1 to 50 parts by weightwith respect to 100 parts by weight worth of SiO₂ of the pure siliconepolymer sol, modified silicone polymer sol, and mixed silicone polymersol, an extremely remarkable effect of improvement of the insulation andbreakdown voltage is achieved and further, as a composite effect, thedeposition power on the core end faces or steel sheet surface isimproved.

Further, by reducing the shrinkage at the time of drying, it is possibleto easily suppress cracking and increase the thickness.

As the filler added at this time, in the case of an inorganic substance,0.1 to 50 parts by weight of one or more of the substances selected fromSiO₂, Al₂O₃, TiO₂, ZrO₂, and composites of the same having a primaryparticle size of 7 to 5000 nm is added and blended as powder particlesor colloidal substances.

In the case of an organic substance, addition and blending of 0.1 to 50parts by weight of one or more substances selected from acryl,polystyrene, polyethylene, polypropylene, polyamide, polycarbonate,polyurethane, melamine, phenol, epoxy resin, and copolymers of the sameof a particle size of 50 to 10,000 nm as an emulsion substance iseffective for improvement of the insulation.

With an amount of addition of less than 0.1 part by weight with respectto 100 parts by weight worth of SiO₂ of all of the silicone polymer, theeffect of improvement of the insulation and adhesiveness is weak. On theother hand, if over 50 parts by weight, the breakdown voltage of thecoating is improved more, but the density of the film is impaired or thelifetime of the solution reduced, so this is set as a limit.

As the filler, in the case of an inorganic oxide, a powder or colloidalsubstance of SiO₂, Al₂O₃, TiO₂, ZrO₂, or a composite of the same isadvantageous since it is low in cost and gives an effect of improvementof the insulation due to the good dispersion and addition.

In the case of an organic type, one or more powders or emulsions etc.selected from acryl, polystyrene, polyethylene, polypropylene,polyamide, polycarbonate, polyurethane, melamine, phenol, and epoxyresins in suitable combination is used.

If considering all together the solution stability, hardness, insulationeffect, heat resistance, etc. in the case of addition, an inorganicadditive is advantageous in that it is lower in cost and gives excellentdispersion and a stable effect of improvement of the insulation andadhesiveness. In particular, the effect is remarkable when performingstrain annealing or another heat treatment step.

The particle size of the filler is important. In the case of aninorganic type filler, when the particle size is less than 7 nm, whendispersed in the solution, the cohesiveness becomes stronger and thecoating thickness becomes uneven or there is an effect on the pH of thesolution and the stability of the solution deteriorates, so this is setas a limit.

On the other hand, when over 5,000 nm, the surface roughness due to thecoarse particles becomes too great and the inorganic substance is liableto detach from the core end faces due to abrasion etc., so this is setas a limit. If in this range, the adhesiveness is good with a balancebetween the film thickness and amount of addition and an insulationcoating having a high breakdown voltage can be formed. This is set as alimit for the same reasons as in the case of an organic type filler.

When adding an additive to the silicone polymer, a more uniformdispersion is desirable. If the powder substance is added after beingdispersed in an alcohol or other solvent, a superior effect ofdispersion is obtained. This is advantageous for obtaining a coating ofa uniform thickness. In particular, a uniform dispersion is obtained ifjointly using dispersion by ultrasonic vibration or dispersion byanother mixer etc.

When drying the core after being coated with a solution, drying atordinary temperature is sufficient, but when trying to dry in a shorttime or improve the efficiency of the process, if drying in a dryingfurnace at a temperature of not more than 300° C. for at least 30seconds, the desolvation and dehydration condensation proceedsufficiently and a good coating performance is obtained. As a preferabledrying method, gradual heating gives good coating properties.

This is because if heating rapidly, water, alcohol, or another solventis rapidly dried and bump like surface defects easily occur.

When using the solution of the present invention for repeated coating totry to obtain a thick coating, to obtain a thicker coating and goodinsulation performance, it is advantageous to first coat and dry asolution containing the filler at a low temperature of room temperatureto 120° C., then coat and dry a solution not containing a filler.

At the time of repeated coating, it is sufficient to coat the coatingagent containing the filler to give an average film thickness afterdrying of 0.2 to 10 μm and then coat a solution not containing a fillerto give 0.5 to 20 μm after drying.

The treatment with reduced content of filler is due to the fact that acombination of coating a large amount of an agent without a filler toflatten the roughness due to the filler makes it easy to obtain aninsulation coating providing high insulation, uniformity, adhesiveness,and corrosion resistance.

Next, the reasons for limitation in a transformer core having a highinsulation will be explained.

The stacked sheets of the magnetic material in the present invention aretreated on their end faces and surfaces with an insulation coatingcomprised of an organic silicon compound and feature superior insulationand corrosion resistance. The coating component of the organic siliconcompound used in the present invention has Si—O bonds and forms anextremely dense coating mainly comprised of an SiO₂ component.Therefore, it is possible to form an insulation coating with anextremely superior insulation and corrosion resistance.

The thickness of the insulation coating of the present invention is made2 to 100 μm. With a thickness of over 2 μm, the breakdown voltagebecomes 40V, which is sufficient for a small-sized transformer. If thethickness is less than 2 μm, depending on the shape of the end faces ofthe core, locally thin portions occur and a stable breakdown voltagecannot be obtained. On the other hand, if the thickness becomes morethan 50 μm, a close to infinite breakdown voltage is obtained. There isno problem even when a high breakdown voltage is required as in the caseof a large-sized transformer. For the upper limit, the coating may bethick, but considering dryability, repeated coating, and adhesiveness ofthe insulation coating at the time of actual work, the limit of themaximum thickness is made 100 μm. Considering the ease of the coatingtreatment, the coating performance, the cost, etc., the most preferablerange is 3 to 30 μm.

Further, the transformer core of the present invention means atransformer core where only the stacked core is treated to giveinsulation and one where a conductor is attached to the stacked core,then they are simultaneously given an insulation coating. In the lattercase, since the stacked core and conductor material are simultaneouslytreated to give an insulation coating, not only insulation, but alsobonding of the core and conductor are simultaneously achieved. Theinsulation coating material permeates to the core end faces, surface,between the steel sheets (foil), between the conductors, and theinterface between the core and conductors. With a dry film, not only arean extremely superior insulation and corrosion resistance obtained, butalso the stacked core material, the conductors themselves, and the coreand conductors are strongly bonded. With an organic silicon compoundcoating of the present invention, a superior insulating and bondedcoating provided with hardness, strength, heat resistance, etc. isobtained depending on the composition.

Next, using as the composition of the solution of the organic siliconcompound used in the present invention one or more types of treatmentagents obtained by preparing a silane expressed by the general formulas;(R¹)_(n)Si(X¹)_(4-n) (where n is an integer of 0 to 3, R¹ is an alkylgroup or phenyl group, the plurality of R¹ able to be different when n=2or 3, X¹ being an alkoxy group expressed by Cl or O(R²), where R² is analkyl group, and the plurality of R² able to be different when n=0, 1,or 2), the end faces and surface are coated and dried one or more timesby at least one of dipping, spraying, and brushing interspaced withdrying. The organic silicon compound is produced by hydrolysis andpolymerization of a known alkoxysilane without a solvent or in anorganic solvent. At this time, by changing the type or combination ofsilanes used, coatings having various types of performance can beobtained.

When producing a partially hydrolyzed product of alkoxysilane as theorganic silicon compound, use is made of one or more oftetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane,tetrabutoxysilane, monomethyltrimethoxysilane,monomethyltriethoxysilane, monomethyltriisopropoxy-silane,monomethyltributoxysilane, monoethyl-trimethoxysilane,monoethyltriethoxysilane, monoethyltriisopropoxysilane,monoethyltributoxy-silane, dimethyldimethoxysilane,dimethyldiethoxy-silane, diethyldimethoxysilane, diethyldietoxysilane,phenyltrimethoxysilane, diphenyldimethoxysilane, phenyltriethoxysilane,and diphenyldiethoxysilane. At that time, as more preferable conditions,if preparing the stock material so that the coating agent contains atleast 50% of one or more types of substances expressed by(R¹)_(n)Si(X¹)_(4-n) (where n is an integer of 0 to 3, R¹ is an alkylgroup or phenyl group, the plurality of R¹ able to be different when n=2or 3, X¹ being an alkoxy group expressed by Cl or O(R²), where R² is analkyl group, and the plurality of R² able to be different when n=0, 1,or 2), a coating superior in insulation, corrosion resistance,adhesiveness, and heat resistance is obtained. When the content issmaller than this, the heat resistance tends to fall and, depending onthe heating conditions, peeling of the film occurs. Most preferable iswhen the agent contains at least 50% of R¹, and at least 5% of X¹. Inthis case, a thick coating superior in adhesiveness and heat resistanceis obtained.

As the organic silicon compound, depending on the method of production,there is a heat curing type treatment agent which gives a partialhydrolyzed product of a silane compound as a reaction in the curingprocess, then is used for treatment and is cured by evaporating thealcohol of the solvent component or moisture by heat and a moisturecuring type which does not undergo partial hydrolysis in the process ofproduction of the organic silicon compound, but is given a curing agent,is used for treatment, then cures by undergoing a hydrolysis andcondensation reaction by the moisture in the air. In the case of thepresent invention, the insulation coating treatment, bundling, andbonding not only of the end faces of the steel sheets, but also betweenthe steel sheets (foil), the spaces between the conductors, and betweenthe steel sheets (foil) and conductors are important. As a morepreferable condition, use of a heat curing type of solution isadvantageous for obtaining quick drying and properties of a stableinsulation coating.

By coating and drying at a low temperature one or more types of organicsilicon compounds comprised of a partial condensate obtained fromsilane, it is possible to form an SiO₂ polymer film superior in coatingperformance.

Further, when trying to obtain a high insulation resistance or breakdownvoltage in the bundling film, 0.1 to 50 parts by weight in terms ofsolid content of inorganic oxide powder particles or colloidal solutionis added as a filler to the organic silicon compound with respect to 100parts by weight worth of SiO₂ contained in the organic silicon compound.As a composite effect of addition of the filler, the deposition power onthe core end faces or steel sheet (foil) surface and crack resistanceand insulation of the coating are improved. As the inorganic powderparticles or colloidal substance added, 0.1 to 50 parts by weight of oneor more types of substances selected from SiO₂, Al₂O₃, TiO₂, ZrO₂,and/or composite substances of the same having a primary particle sizeof 7 to 5000 nm is added. If the amount of addition is less than 0.1part by weight, an effect of improvement of wetability, crackingresistance, and insulation is not obtained. Further, if over 20 parts byweight, poor bundability and adhesiveness and film unevenness easilyoccur. The best range of addition is 0.4 to 2 parts by weight.

The method of coating the above organic silicon compound may be thegenerally used method of applying a surface coating, painting etc. Themethod of not only spray coating and dipping, but also brushing may beused. It is also possible to use general methods for suppressingunevenness of the amount of coating etc. Further, to improve the bondingpower of the contact parts of the conductors, magnetic materials, etc.,it is possible to secure bundling power after drying if giving clearanceonce at the contact parts, impregnating the bundling solution in thecontact parts, and then establishing a predetermined contact state.

The dried thickness is easy to control by the method of changing thetype of the solvent of the solution or the concentration or viscosity ofthe solvent. If performing the coating and drying step several times, itis possible to increase the film thickness by that amount. The coatingis applied to a predetermined thickness by controlling the pullout speedin the case of dipping and the nozzle shape, ejection speed, etc.together with the above solution conditions in the case of spraying.Further, it is possible to suppress solution buildup and adjust the filmthickness by blowing compressed air.

The electrical insulation coating formed in the present invention alsohas a bundling function. Further, it also serves as a rust preventingfilm. That is, it is possible to coat only the core end faces orpossible to attach the winding and then coat the winding to fasten it.The dried film of the present invention is mainly comprised of SiO₂ andforms a dense film having Si—O bonds, so exhibits an extremely superiorinsulation and rust prevention function.

When using the organic silicon compound of the present invention, thedrying temperature should be not more than 200° C. This is because thesolvent making up part of the organic silicon compound is mainly methylalcohol, ethyl alcohol, butyl alcohol, propyl alcohol, water, or anotherlow temperature volatilizing solvent. The preferable drying temperatureis 80 to 120° C. By using a low boiling point solvent, this dryingtemperature becomes possible. If in this temperature range, drying in ashort time of several minutes becomes possible.

In a large-sized, medium-sized, and small-sized transformer for poweruse, the flow of a short-circuiting current itself is a serious problemand must not be allowed. The present invention also takes note of theproblems in work efficiency, cost, and the work environment caused bythe varnishing and other treatment conventionally performed afterdeburring and other treatment of the end faces of core materials. If theorganic silicon compound of the present invention is used, properties(functions) above those of varnishing are secured and these problems arealleviated.

As the electrical apparatuses in the present invention, there areelectromagnetic apparatuses and heaters. The electromagnetic apparatusesinclude motors, actuators, generators, transformers, reactors, etc. Theheaters uses induction heating, heating by irradiation by infrared raysor other light and electromagnetic waves, and heating by directconduction. The application and model are irrelevant.

The motors, actuators, and generators come in an induction machine type,synchronous machine type, DC machine type, reactance type, or two ormore types in combination and include large-sized to micro motors.Further, transformers include wound transformers, stacked transformers,and other types using various types of cores. Reactors are used forinverters, converters, choppers, apparatuses used for adjusting thephase of the voltage and current and improving the power factor, filtersfor eliminating high frequencies etc., ignitions, etc. There are woundtypes, stacked types, types with clearances and types without,saturatable types, types used not allowing saturation, types using cutcores, etc. Types having cores or yokes and types not having them areboth possible. Further, types having permanent magnets and types nothaving them are both possible.

The core and yoke include magnetic steel sheet, permalloy metal,iron-cobalt alloy, amorphous magnetic material core, and other stackedcores, soft ferrite cores, cast cores, powder metallurgical cores,plastic formed cores of powder, etc. The materials of the core and yokeinclude magnetic steel sheet, plate, and other ferrous metals or ferrousmetal alloys, nickel, permalloy metal, and other nickel alloys, cobaltand cobalt alloys, and soft ferrite, amorphous materials, nanocrystalmaterials, etc. The applications include armature cores, field yokes,transformer cores, reactor cores, electromagnet cores, printed circuitboards, etc. In particular, much use is made of cores and yokes obtainedby punching and stacking magnetic steel sheet. Cores include coresobtained by punching and stacking single pieces, cores usingcombinations of divided core pieces, and wound cores sometimes used foraxial gap type rotary machines such as in rotary machines, plasticdeformed cores such as claw pole cores, wound cores, stacked cores,sintered cores, powder molded cores, plastic formed cores, etc. such asin transformers or reactors, cut cores, EI cores, etc. The presentinvention can be applied to all of these.

The permanent magnets are not limited in type or shape and are not onlyused for fields for motors, actuators, and generators, but are also usedfor the bias magnetic flux (magnetic field) used in flyback transformersand reactors.

Electromagnetic apparatus, as explained above, use numerous magneticmembers such as armature cores, permanent magnets, field yokes, etc.Even armature cores, field yokes, etc. are often comprised from aplurality of pieces of magnetic materials such as in the stacking ofmagnetic steel sheet.

Electromagnetic apparatuses are sometimes magnetically shielded orelectromagnetically shielded so as to prevent magnetic flux from leakingto the outside or to prevent external magnetic flux from invading theapparatus and having a detrimental effect on the outside or inside ofthe apparatus. The magnetic members of the present invention includemagnetic members for magnetic shielding and electromagnetic shielding.In this case, the electromagnetic apparatuses to which the presentinvention relates include apparatuses, devices, and facilitiesgenerating magnetic flux and electromagnetic waves and converselyincludes apparatuses, devices, and facilities affected by magnetic fluxand electromagnetic waves. Further, the invention can also be applied togeneral magnetic shielding materials and electromagnetic shieldingmaterials.

Electrical apparatuses use conductors. The conductors of electromagneticapparatuses carry armature current or carry current generating a fieldmagnetic flux. They may be provided at the stator side or provided atthe rotor or moving piece side. The secondary conductors carrying theinduction current such as in induction machines, the short rings usedfor voice coil motors, etc. are also included as conductors. Theconductors of the heaters are heating elements etc. Further, the leadwires and wirings used in electrical apparatuses are included in theconductors of the present invention.

The high temperature operating electrical apparatuses of the presentinvention include ones used at a high temperature and used at hightemperature environments and ones which become high in temperature bythe heat generated from the conductors or magnetic materials. Therefore,the electrical insulation and magnetic flux retention of the conductorsor magnetic materials have to be able to breakdown even hightemperatures. The heat resistance temperature of the insulation coatingor adhesive applied to conventional conductors was normally the 180° C.of the H type of the JIS (Japan Industrial Standard) at the maximum. Inthe present invention, the “high temperature” means a temperature rangeof from 200° C. to 900° C. inclusive. If the temperature becomes higherthan 900° C., mechanical problems arise in the conductors themselves.According to the present invention, it becomes possible to provide anelectrical apparatus able to operate even at such a temperature.

In the present invention, a solution exhibiting the ability to fastenand bundle conductors or magnetic material and the ability to maintainthe electrical insulation or fastening and bundling of conductors ormagnetic materials at a high temperature (hereinafter referred to as a“bundling solution”) upon drying is coated or the bundling solution isdipped into so as to deposit the bundling solution on the outside of theconductors or magnetic materials or impregnate the bundling solution atthe contact parts between conductors, between magnetic materials,between conductors and magnetic materials, and between conductors,magnetic materials, and other members. Next, the bundling solution ismade to dry at ordinary temperature or more to bundle the conductors andmagnetic materials or these and other members. The drying condition inthe present invention is sufficient drying at room temperature to 120°C. or so, but by drying at 80 to 200° C. for at least 30 seconds toobtain a sufficient coating effect, extremely fast drying and curingbecome possible.

In the present invention, the coating formed by drying the bundlingsolution covers the outside surfaces of the magnetic materials or othermembers etc. and bundles them together. Alternatively, the bundlingsolution invades the adjoining conductors, magnetic materials, etc. andbonds and bundles them when dried. (Hereinafter the coating or layerformed after drying of the bundling solution being referred to as a“bundling film”.) Therefore, since the bundling power is determined bythe type and thickness of the bundling film, it is sufficient todetermine the type of the bundling solution and film thickness inaccordance with need. Further, the bundling power changes according tothe shapes of the conductors and magnetic materials and the state of thesurface or end faces, so it is necessary to consider the shapes of theconductors and magnetic materials and the state of the surface or endfaces as well.

As the bundling solution, a solution mainly comprised of one or moretypes of pure silicone polymers is used. A pure silicone polymer is acompound produced by a hydrolysis reaction and dehydration condensationreaction of, one or more types of organic silicon compounds expressed by(R¹)_(n)Si(X¹)_(4-n) (where n is an integer of 0 to 3, R¹ is an alkylgroup or phenyl group, the plurality of R¹ able to be different when n=2or 3, X¹ being an alkoxy group expressed by Cl or O(R²), where R² is analkyl group, and the plurality of R² able to be different when n=0, 1,or 2). These are produced by hydrolysis and polymerization of a knownalkoxysilane without a solvent or in an organic solvent. At this time,by changing the type of the silane used, coatings having variousperformances are obtained.

In general, pure silicone polymers include types called a heat curingtype and moisture curing type. In the present invention, the former heatcuring type is preferably used. The “heat curing type”, as explainedabove, is comprised of an organic silicon compound, methanol, ethanol,isopropanol, butanol, or other alcohol having a low boiling point, andwater. Therefore, in the curing process, by drying at a low temperatureof about 120° C. or less, the solvent component can be vaporized andexpelled in an extremely short time and a dense coating of Si—O bondscan be formed by drying for several minutes to several tens of minutes.In the case of the latter moisture curing type, a hydrolysis reaction iscaused by absorption of the moisture in the air and the coating is curedand a coating formed by the effect of the added catalyst. Therefore,sometimes it takes several days for the curing of the coating toproceed. Further, in this case, the formation and curing of the coatingare not achieved unless moisture is supplied from the atmosphere. Whenapplied to stacked sheets, in particular large area materials as in theapplications of the present invention, the curing proceeds at the endfaces and supply of moisture into the interior becomes difficult sosometimes the coating at the inside cannot be cured even after severalweeks and therefore there is the problem that constant of the curingtime cannot be obtained.

In the heat curing type of the present invention, if heating to morethan the boiling point of the solvent, the solvent can be simply brokendown and expelled. This is an extremely great merit in terms ofindustrialization.

Further, when trying to obtain a high insulation resistance andbreakdown voltage in the bundling coating, 0.1 to 50 parts by weight interms of solid content of one or more types of inorganic oxide powderparticles or a colloidal solution, organic resin powder particles, or anemulsion solution of the same is added to the silicone polymer as afiller with respect to 100 parts by weight worth of SiO₂ of the puresilicone polymer. As a composite effect of addition of this filler, thedeposition power to the core end faces or steel sheet surface isimproved. As the inorganic powder particles or colloidal substanceadded, 0.1 to 50 parts by weight of one or more types of SiO₂, Al₂O₃,TiO₂, ZrO₂, and/or composites of the same having a primary particle sizeof 7 to 5,000 nm is added and blended. Since the conditions of use havean effect on the stability of the solution, use of a substance having aprimary particle size of not more than 0.5 μm is more preferable.

In the present invention, when trying to obtain a bundling film superiorin heat resistance, if the organic silicon compound contains at least80% of at least n=0, 1 in the general formula expressed by(R¹)_(n)Si(X¹)_(4-n) (where n is an integer of 0 to 3, R¹ is an alkylgroup or phenyl group, the plurality of R¹ able to be different when n=2or 3, X¹ being an alkoxy group expressed by Cl or O(R²), where R² is analkyl group, and the plurality of R² able to be different when n=0, 1,or 2), and if making the ratio of the case where n=0 and the case wheren=1 a range of 1:20 to 4:1, a more superior performance of the bundlingfilm is obtained. In particular, the higher the ratio of the componentof n=0, the greater the hardness of the coating. Further, the obtainedbundling film becomes resistant to cracking. This is advantageous foruse at the time of use at a high temperature. Further, in general, thedrying is fast and the work efficiency in drying is improved. However,as the n=0 component becomes too hard, there is a problem that a thickcoating can no longer be obtained due to the problem of cracking in theprocess of drying of the coating. That is, when the ratio of the casewhere n=0/case where n=1 is less than 0.05 (1:20), the heat resistancebecomes inferior, so this is set as a limit. On the other hand, if theratio becomes more than 4 (4:1), the heat resistance is improved, butthere is the problem of cracking of the coating and obtaining a thickcoating becomes difficult, so this is set as a limit.

To increase the electrical insulation, it is sufficient to add and blendas an additive 0.1 to 10 parts by weight of one or more compoundsselected from SiO₂, Al₂O₃, TiO₂, and mixtures of the same having aprimary particle size of 7 to 5,000 nm.

The method of coating the bundling solution or the method of dipping inthe bundling solution may be a generally used method of surface coatingor painting etc. In addition to spray coating and dipping, brushing oranother method may also be used. The unevenness of the amount of coatingetc. may also be suppressed by a generally used method. Further, toimprove the bonding power at the contact parts of the conductors,magnetic materials, etc., by giving a clearance to the contact partsonce, impregnating the bundling solution at the contact parts, thenestablishing the predetermined contact state, the bundling power afterdrying can also be increased.

The dried thickness of the bundling film is easy to control by themethod of changing the type of the solvent of the bundling solution orthe concentration or viscosity of the solvent. If performing the coatingand drying step several times, it is possible to increase the filmthickness by that amount. The coating is coated to a predeterminedthickness by controlling the pullout speed in the case of dipping andthe nozzle shape, ejection speed, etc. together with the above solutionconditions in the case of spraying. Further, it is possible to suppresssolution buildup and adjust the film thickness by blowing compressedair.

The bundling film formed in the present invention may also serve as anelectrical insulation coating when electrical insulation is sought andmay also serve as a rust-preventing coating. The dried coating accordingto the present invention is mainly comprised of SiO₂ having an Si—Ostructure and forms a dense film, so exhibits extremely superiorinsulation and rust prevention functions.

EXAMPLE 1

A cold rolled coil of non-oriented magnetic steel sheet containing 0.35%of Si, 0.002% of Al, and 0.25% of Mn and having a thickness of 0.50 mmwas annealed on a continuous annealing line, then a solution comprised,in terms of solid content, of 450 parts by weight of Mg, 120 parts byweight of boric acid, and 5 parts by weight of an acryl-styrene resinemulsion by weight after baking was baked on as an insulation coatingagent on the same line at a sheet temperature of 350° C.

Next, a core of a rotor of a 2.2 kw, 200V, and 60 Hz three-phasefour-pole cage type induction motor (44 slots, semiclosed, with skew(1.23 times pitch of stator slots)) was prepared by punching pieces outfrom this coil and calking.

The core was dipped in a coating agent for deposition on the end facesusing a solution of the composition shown in Table 1 while changing thethickness of the film after drying, dried at ordinary temperature, andbaked at 100° C. for 10 minutes. Next, secondary conductor bars wereformed by aluminum diecasting on the core and a shaft inserted tofabricate a rotor of the above induction motor. The loss was found fromthe no-load characteristics of the motor to confirm the effect of thepresent invention.

Further, at this time, some of the annealed material (before treatmentto give an insulation coating) was taken from the production line of thenon-oriented magnetic steel sheet, 10×30 cm samples were cut out, andthe samples were coated with the above solution using a bar coater whilechanging the thickness of the coating after drying, then similarlybaked, and used for evaluation of the breakdown voltage, coatingdensity, corrosion resistance, etc.

The state of coating and magnetic characteristics of the core in thetest and the results of evaluation of the insulation coatings before andafter annealing in materials coated on the surface of steel sheet areshown in Table 2 and Table 3.

As a result of this test, when treating the core end faces with theinsulation coating agent of the present invention, a transparent coatingwith good luster was formed and an extremely superior corrosionresistance and heat resistance were exhibited. As opposed to this, inthe case of treating a comparative material with a conventional varnishor insulation coating agent, oil deposited at the time of punching had agreat effect. The insulation coating deposited unevenly, so thecorrosion resistance ended up becoming extremely poor compared with acore coated with the agent of the present invention.

Further, even when cleaning off the oil using acetone as pre-treatmentin Comparative Examples 1 and 2, the state of deposition of the coatingon the end faces became uneven and results considerably inferior tothose of the present invention were obtained even in the coatingproperties.

Further, a comparison of the rate of reduction of iron loss of the coreshowed that the losses of motors treated in Invention Examples 1 to 12were reduced 7 to 17%. Further, in the case of Comparative Examples 13and 14, improvements of about 4.5% were seen. As opposed to this, in thecase of Comparative Example 1, almost no reduction of the loss was seen.Further, in the case of Comparative Example 1, the loss was reduced 5%.In the motor performance as well, with the insulation treatment of thepresent invention, the loss was clearly reduced compared with theconventional non-insulation treatment or conventional treatment and ahigher efficiency of the motor was realized.

Further, looking at the coating properties when conducting a coatingtest by a bar coater using a cut sheet agent, as shown in Table 3, inthe case of use of the agent of the present invention, the corrosionresistance, insulation, and adhesiveness were all extremely excellent.In particular, in the case of coating the pure silicone polymer byhydrolysis of alkoxysilane of Invention Examples 1 to 8, 10, and 11, itwas confirmed that extremely excellent results were obtained in thebreakdown voltage after annealing as well.

In the example of the mixed silicone polymer of Invention Example 12 aswell, considerably good breakdown voltage and coating properties wereobtained. Further, in the case of the alkali silicate, colloidal silica,and silicone resin of Invention Examples 13 and 14, while the breakdownvoltage, corrosion resistance, and adhesiveness were somewhat inferiorto those of the case of the above pure silicone polymer, stable coatingperformance was obtained compared with the comparative examples.

As opposed to this, in the case of Comparative Examples 1 and 2, thecorrosion resistance and adhesiveness were extremely poor compared withthe present invention. In particular, with the conventional varnishing,the coating was substantially completely burned off after annealing andblackened and the corrosion resistance and insulation properties wereextremely poor compared with the present invention.

TABLE 1 Treatment Thickness conditions Treatment agent conditions (μm)Drying conditions Inv. Ex. 1 Hydrolyzed product of tetramethoxysilane,(SiO₂ concentration 10%): 70 cc  1.5 Room temp. 15 min -> Hydrolyzedproduct of monomethyltriethoxysilane (SiO₂ concentration 10%): 30 cc100° C. × 5 min Inv. Ex. 2 Hydrolyzed product of tetramethoxysilane(SiO₂ concentration 10%): 70 cc  3.0 Room temp. 15 min -> Hydrolyzedproduct of monomethyltriethoxysilane (SiO₂ concentration 10%): 30 cc100° C. × 5 min Inv. Ex. 3 Hydrolyzed product of tetramethoxysilane(SiO₂ concentration 10%): 70 cc  5.0 Room temp. 15 min -> Hydrolyzedproduct of monomethyltriethoxysilane (SiO₂ concentration 10%): 30 cc100° C. × 5 min Inv. Ex. 4 Inv. Ex. 3 double coating(coating->drying-coating->drying) 10.0 Room temp. 15 min -> 100° C. × 5min Inv. Ex. 5 Hydrolyzed product of monomethyltriethoxysilane (20%): 75cc  5.0 Room temp. 5 min -> Hydrolyzed product of tetraethoxysilane(20%): 15 cc 150° C. × 5 min Hydrolyzed product ofdimethyldiethoxysilane (20%): 10 cc Inv. Ex. 6 Hydrolyzed product ofmonomethyltrimethoxysilane: 100 cc +  1.5 Room temp. 5 min -> particlesize 15 nm Al₂O₃ 1% - SiO₂ mixed powder:  1.5 g 150° C. × 5 min Inv. Ex.7 Hydrolyzed product of monomethyltrimethoxysilane: 100 cc +  5.0 Roomtemp. 5 min -> particle size 15 nm Al₂O₃ 1% - SiO₂ mixed powder: 1.5 g150° C. × 5 min Inv. Ex. 8 Inv. Ex. 7 -> Inv. Ex. 5 (double coating)1.5 + 3.5 Room temp. 5 min -> 150° C. × 5 min Inv. Ex. 9 Alkali-modifiedsilicone (acrylic monomer, methacrylsilane reaction product)  5.0 Roomtemp. (25° C.) 120 min Inv. Ex. 10 Hydrolyzed product oftetramethoxysilane (SiO₂ concentration 10%): 70 cc  5.0 Room temp. 15min -> Hydrolyzed product of monomethyltriethoxysilane (SiO₂concentration 10%): 30 cc 100° C. × 5 min Inv. Ex. 11 Hydrolyzed productof dimethyldimethoxysilane (15%): 20 cc  5.0 Room temp. 15 min ->Hydrolyzed product of phenyltriethoxysilane (15%): 30 cc 100° C. × 5 minHydrolyzed product of tetraethoxysilane (15%): 50 cc + particle size 500nm SiO₂ powder: 2.5 g Inv. Ex. 12 Polydiphenylsiloxane polymer  5.0 150°C. × 20 min Inv. Ex. 13 Alkali silicate (Na₂O.SiO₂) 100 g + colloidalsilica (30%) 50 g  5.0 100° C. × 15 min Inv. Ex. 14 Silane diol polymer 5.0 150° C. × 15 min Comp. Ex. 1 Polyimide varnish  5.0 150° C. × 2 hrComp. Ex. 2 50 Al phosphate 100 L + CrO₃ 10 kg + 30% colloidal silica 40L  5.0 300° C. × 10 min

TABLE 2 Treatment Coating-forming state Corrosion resistance End facecoating state after conditions (appearance after conditions drying) (50°C., 120 hr, humidity 80%) annealing of core*1 Inv. Ex. 1 VG, uniformtransparent coating formed VG, no rust occurring VG, no change at allInv. Ex. 2 VG, uniform transparent coating formed VG, no rust occurringVG, no change at all Inv. Ex. 3 VG, uniform transparent coating formedVG, no rust occurring VG, nc change at all Inv. Ex. 4 VG, uniformtransparent coating formed VG, no rust occurring VG, no change at allInv. Ex. 5 VG, uniform transparent coating formed VG, no rust occurringVG, no change at all Inv. Ex. 6 VG, uniform transparent coating formedVG, no rust occurring VG, no change at all Inv. Ex. 7 VG, uniformtransparent coating formed VG, no rust occurring VG, no change at allInv. Ex. 8 VG, uniform transparent coating formed VG, no rust occurringVG, no change at all Inv. Ex. 9 VG, uniform transparent coating formedVG, no rust occurring G, some blackening, luster Inv. Ex. 10 VG, uniformtransparent coating formed VG, no rust occurring VG, no change at allInv. Ex. 11 VG, uniform transparent coating formed VG, no rust occurringVG, no change at all Inv. Ex. 12 VG, uniform transparent coating formedVG, no rust occurring VG, no change at all Inv. Ex. 13 F-G, transparent,some coating unevenness G, slight rust at unevenly coated G, someblackening, luster parts Inv. Ex. 14 VG, uniform transparent coatingformed VC, no rust occurring G, some blackening, luster Comp. Ex. 1A*2)F, brown, much coating unevenness F, much rust at poorly coated parts P,blackening, no luster Comp. Ex. 1B*3) G, brown, some coating unevennessG-F, some rust at unevenly coated P, blackening, no luster parts Comp.Ex. 2A*2) F-P, white turbidity, much coating F-P, much rust at poorlycoated parts F-P, white turbidity, majority unevenness P, much rust atpoorly coated parts detached Comp. Ex. 2B*3) P, very much coatingunevenness F-P, white turbidity, majority detached *1) Annealing: 700°C. × 5 min, N₂. *2) Comp. Ex. 1A and 2A are as punched in same way asInv. Ex. 1 to 14. *3) Comp. Ex. 1B and 2B are degreased by solvent(acetone dipping and washing) as pre-treatment.

TABLE 3 Breakdown voltage Adhesiveness*⁴⁾ (n = 10 average) Coatingforming state Corrosion resistance (50° C., Before After Before After(appearance after drying) 120 hr, humidity 80%) annealing annealing*⁵⁾annealing annealing*⁵⁾ Inv. Ex. VG, uniform transparent VG, no rustoccurring VG, no VG, no peeling  80  78 1 coating formed peeling Inv.Ex. VG, uniform transparent VG, no rust occurring VG, no VG, no peeling200 200 2 coating formed peeling Inv. Ex. VG, uniform transparent VG, norust occurring VG, no VG, no peeling 220 230 3 coating formed peelingInv. Ex. VG, uniform transparent VG, no rust occurring VG, no VG, nopeeling 260 250 4 coating formed peeling Inv. Ex. VG, uniformtransparent VG, no rust occurring VG, no VG, no peeling 250 210 5coating formed peeling Inv. Ex. VG, uniform transparent VG, no rustoccurring VG, no VG, no peeling 180 200 6 coating formed peeling Inv.Ex. VG, uniform-transparent VG, no rust occurring VG, no VG, no peeling300< 300< 7 coating formed peeling Inv. Ex. VG, uniform transparent VG,no rust occurring VG, no VG, no peeling 300< 300< 8 coating formedpeeling Inv. Ex. VG, uniform transparent VG, no rust occurring VG, no G,some peeling 150  40 9 coating formed peeling Inv. Ex. VG, uniformtransparent VG, no rust occurring VG, no G-VG, some 250 220 10 coatingformed peeling peeling Inv. Ex. VG, uniform transparent VG, no rustoccurring VG, no G-VG, some 300< 300< 11 coating formed peeling peelingInv. Ex. VG, uniform transparent VG, no rust occurring VG, no VG, nopeeling 250 200 12 coating formed peeling Inv. Ex. VG, uniformtransparent G, some rust occurring VG, no G, some peeling 130  60 13coating formed peeling Inv. Ex. VG, uniform transparent VG, no rustoccurring VG, no F-G, some 150  40 14 coating formed peeling peelingComp. Ex. F, brown, no luster, G-F, rusting at unevenly F, 50% P,complete 100  0 1 uneven color coated parts peeling peeling Comp. Ex. P,white turbidity, much F, much rust occurring F, 95% G, small 160 120 2uneven coating peeling peeling *⁴⁾Bent face observed after 5 mmφbending. *⁵⁾Annealing: 700° C. × 30 sec, atmosphere N₂, surfaceappearance after annealing

EXAMPLE 2

Each agent of the present invention of the pure silicone polymercompositions shown in Table 4 was used in the same way as in Example 1to bake an insulation coating to give a film thickness after drying of 5μm on the surface of non-oriented magnetic steel sheet of a sheetthickness of 0.5 mm. Next, the steel sheet with this insulation coatingwas stacked, annealed at 400° C.×1 hr in the air, and examined as to theheat resistance of the coating. The results are shown in Table 4.

As a result of the tests, when treating sheets with solutions based onthe pure silicone polymers of the present invention, in each case, atransparent lustrous coating state was maintained even after annealingat 400° C. for 1 hour and no drop in adhesiveness or insulation could beobserved. As opposed to this, in the case of an organic type varnish ofthe comparative material, a remarkable drop in the surface appearance,adhesiveness, and insulation occurred due to the annealing.

TABLE 4 Adhesiveness Breakdown voltage Surface appearance afterannealing Before After Treating agent conditions after annealing (10 mmφbending) annealing annealing Inv. Ex. Hydrolyzed product oftetraethoxysilane: 50 cc Transparent, No peeling 230 220 1 Hydrolyzedproduct monomethyltriethoxysilane: 50 cc luster Inv. Ex. Hydrolyzedproduct of monomethyltriethoxysilane: 70 cc Transparent, ″ 240 250 2Hydrolyzed product of tetraethoxysilane: 15 cc luster Hydrolyzed productof dimethyldiethoxysilane: 15 cc Inv. Ex. Hydrolyzed product ofdimethyldimethoxysilane: 40 cc Transparent, ″ 270 260 3 Hydrolyzedproduct of phenyltriethoxysilane: 10 cc luster Hydrolyzed producttetraethoxysilane: 50 cc Particle size 15 nm Al₂O₃ powder: 0.5 g Inv.Ex. Hydrolyzed product of monomethyltriethoxysilane: 70 cc Transparent,″ 300< 300< 4 Hydrolyzed product of tetraethoxysilane: 15 cc lusterParticle size 200 nm SiO₂ powder: 2 g Comp. Ex. Polyimide varnishBlack-brown, no Much peeling  65  10 1 luster

EXAMPLE 3

A stator (armature) core treated on its surface using the presentinvention was used to prepare a microturbine generator. The stator corewas obtained by punching from a magnetic steel sheet and calking and hasbolt holes for fastening the core.

Next, the stator core was treated by Invention Example 1 of Example 1,the stator core was inserted into the case, then the core was bolted. Inthe past, since the core contacted the case or bolts and the calkedlayers contacted each other, a short-circuiting current flowed throughthe core, so the loss increased and there was a large temperature risein the stator. If applying the present invention, it is possible toreduce and avoid the above short-circuiting current and possible to keepthe temperature rise down to an average 3 degrees.

EXAMPLE 4

Cores treated on their end faces utilizing the present invention werecombined to produce an XY linear motor. In this XY linear motor, sincethe flow of magnetic flux was three dimensional, cores punched out fromordinary magnetics steel sheet were combined at right angles.

Conventional cores contacted each other at their end faces, butinsulation paper was sandwiched between the cores, so in the case ofcore contact, there was an increase in loss due to contact of the endfaces and much variance in performance. On the other hand, if insulationpaper was inserted, the clearance became relatively greater, theexcitation current became greater, and an increase in the no-loadresistance loss was caused.

If the insulation treatment method of the present invention was used totreat the end faces of the U-shaped cores and two cores were combined,the loss was reduced and variance in performance was also reduced.

EXAMPLE 5

The core of a pump motor was protected from corrosion by wrapping astainless steel cover at the clearance side between the rotor and statorto protect the core in the case of use of magnetic steel sheet for thecore material or using ferritic stainless steel for the core material.

In the former case, the structure was complicated. An eddy current lossoccurred at the stainless steel cover, the clearance became greater,etc., so a drop in output was unavoidable. In the latter case, since thesaturation magnetization of the ferritic stainless steel was low, a dropin output was caused. Therefore, the motor was produced by treating acore made of magnetic steel sheet according to the present invention.

The core treated for insulation by the present invention was alsotreated at its end faces. It was superior in corrosion resistance,needless to say, and also simple in structure and could be made usinghigh saturation magnetization magnetic steel sheet, so there was noproblem in a drop of output. There was no rust even after 100 hours ofoperation, and the motor performance was the same as an ordinary motorother than a pump motor.

EXAMPLE 6

A 50H800 non-oriented magnetic steel sheet was punched, strain annealed,and used to produce a core for use for a small-sized 48 mm audio powertransformer. The capacity was 100VA (100V/6V:1A/16A).

In this case, condition 1 was that it be punched while being calked,while condition 2 was that it be punched without being calked.

The present invention was applied to condition 2. That is, the coresurface, including the end faces, was sprayed with a partial condensateobtained from diphenyldiethoxysilane,dimethylmonomethyltriethoxy-silane, and tetraethoxysilane in a 1:4:5ratio and dried to form a film. At this time, the coating treatment wasperformed twice, accompanied with drying by warm air at 75° C. for 5minutes, to obtain an average film thickness of 7 μm. Next, the windingwas attached to complete the assembly.

Condition 1 was used to produce a power transformer by a conventionalmethod without using the present invention. The transformer of condition1 did not have its core completely fastened. Noise occurred and it wasnecessary to provide holders for separate fastening. With thetransformer of condition 2 according to the present invention, however,there was almost no noise from the core and extra holders were notrequired.

EXAMPLE 7

The present invention was used to produce a brushless DC motor of afour-pole motor. The bundling solution used was a partial condensate(concentration 20%) obtained from monomethyltrimethoxysilane andtetramethoxysilane in a ratio of 3:1 in parts by weight which was driedto form a bundling film. The stator was an armature comprised of 12divided core pieces (core pieces 1 shown in FIG. 2 stacked together).The outside diameter of the assembled circular core was 120 mm. Thedivided core pieces 1A were punched from magnetic steel sheet andstacked. The centers of the magnetic steel sheets at the top and bottomof the stack were held by the bars 4 a and 4 b of FIG. 3 to fasten thestack. Bundling solution was coated on only the punched end faces—notthe end faces of the teeth 2 corresponding to the clearance side withthe rotor. Next, the stack was dried at room temperature while fastenedto form the bundling film. The bundling solution was coated by themethod of sufficiently coating only the processed end faces by brushing.In this case, the bundling solution was impregnated in the brush andcoated so as to give an average film thickness after drying of 10 μm atthe clearance 5′ (FIG. 4) formed by the sloped parts of the punching atthe processed end faces of the stacked core.

Next, the winding 6 was directly wound around the divided core pieces 1Bhaving the bundling film while drying the bundling solution as shown inFIG. 5. Further, as shown in FIG. 6, the portions other than theclearance side were dipped in the bundling solution and dried. Due tothis, the winding was fastened and the bundling strength and rigidity ofthe core was heightened. Next, the divided core pieces were assembled,cauls 9 a and 9 b were placed against the top and bottom surfaces of thecore pack of the core, and simultaneously the assembly was press fitinto the case 10. When placing the cauls, the bundling solution wascoated on the surfaces contacting the core and then the cauls placed onthe core. The assembly of the divided core pieces with the cauls placedwas then coated with the bundling solution on its outer circumferenceand press fit into the case as shown in FIG. 6. Next, this wascompletely dried.

If using the method of the present invention, electrical insulation andfastening and bundling between the conductors, between layers of themagnetic steel sheet, between the conductors and divided core pieces,between the divided core pieces, and between the core and the casebecome possible from ordinary temperature to the temperature of thestate which the permanent magnets used in the motor can breakdown ormore than 500° C. Therefore, since this is higher than the conventional200° C. heat resistant winding temperature, it is possible to pass alarger current through the winding and obtain a higher output. Further,the rigidity of the motor as a whole becomes higher and thereforebecomes one means against noise and vibration. If using bundlingaccording to the present invention, it is possible to suppress theshort-circuiting current causing a problem in calking, welding, etc. andto reduce the loss and improve the controllability. Further, it ispossible to improve the escape of the heat generated from the conductorsand core through the bundling film of the present invention. From thisviewpoint as well, this is effective in raising the output of the motorand lowering the resistance loss (suppressing the increase in resistancedue to the rise in temperature).

EXAMPLE 8

A four-pole IPM (implanted magnet) motor was produced by the armatureproduced in Example 7 and the IPM rotor using the present invention.This motor is controlled in torque at a low speed. The motor was dippedin a bundling solution comprised of a partial condensate obtained frommonomethyltriethoxysilane and tetraethoxysilane in a 1:3 ratiocontaining, as a filler with respect to 100 parts by weight of the sameconverted to SiO₂, 2 g of Al₂O₃ of a particle size of 10 nm to give anaverage film thickness after drying of 5 μm. This was dried to form abundling film.

A magnetized SmCo sintered magnet was dipped in the bundling solutionand dried. As shown in FIG. 8, this magnet 12 was inserted into the IPMrotor core 11. The rotor core with the magnet inserted was also dippedin the bundling solution. The excess bundling solution was removed whilespraying compressed gas, then the core was press fit over a shaft 13.This assembly was then dried to form the bundling film 14 of the partialcondensate. Use of the present invention for the rotor serves both tofasten the magnet and insulate the surface of the magnet from ordinarytemperature to the temperature of the state which the SmCo magnet canbreakdown (about 500° C.). Further, it can improve the heat conductivityand insulation between the magnet and the core and suppress the rise intemperature of the magnet and suppress short-circuiting current betweenthe magnet and core. The clearance between the rotor and shaft is filledby the bundling film and serves to suppress the rise in temperature ofthe rotor. An SmCo magnet can be used at a higher temperature than anFeNdB magnet, but the temperature rise of the SmCo sintered magnet canalso be suppressed and the reduction of magnetization of the magnet canalso be suppressed.

EXAMPLE 9

The present invention was used to produce a two-pole induction motor.The bundling solution used was a partial condensate obtained fromdiphenylethoxysilane, dimethylmonomethyltriethoxysilane, andtetraethoxysilane in a 1:5:4 ratio. This was dried to form a bundlingfilm. The stator core was an integral punched core provided with calkingfor provisional fastening at three locations at equal distances in thecircumferential direction 2 mm from the outer circumference. Thebundling solution was sprayed onto the slot of the core as a whole anddried to form a bundling film. At this time, coating treatment wasperformed two times interposed with drying by warm air at 5° C. for 5minutes to obtain an average film thickness of 7 μm. Next, the bundlingsolution was deposited on the armature winding and the surface of thewinding dried. The dried winding was inserted into the slot of thestator core by an inserter. Next, the armature as a whole was dipped inthe bundling solution. 100° C. hot air was blown from the clearance sidewith the rotor to blow away solution deposited on the teeth-edges inexcess to reduce the film thickness of the clearance surface to lessthan 0.1 mm. The 100° C. hot air had the effect of speeding up thedrying. Finally, this was dried at 300° C. to form the final bundlingfilm.

If the present invention is used, use is possible up to 500° C. Bundlingof the stacked core up that temperature, suppression of theshort-circuiting current, reduction of noise by reduction of vibrationof the teeth-edges, increase of output by higher heat discharge, andlower resistance loss (suppression of increase in resistance due totemperature rise) can be expected.

EXAMPLE 10

An induction motor was produced by the armature core produced in Example9 and an aluminum diecast rotor using the present invention. The rotorwas obtained by dipping a punched core into a bundling solution anddrying to bundle it, then performing aluminum diecasting. The bundlingsolution used was a mixed solution of monomethyltrimethoxysilane,tetramethoxysilane, and dimethyldimethoxysilane in a 5:3:2 ratio. Thiswas dried to form a bundling film.

The bundling film formed by drying can breakdown even aluminumdiecasting, so short-circuits between the secondary conductor aluminumconductors and core can be suppressed. Therefore, stabilization of thehigh output performance of the induction motor can be realized.

EXAMPLE 11

A bundling solution was coated and dried on the surface of a winding.The winding was attached, then the wound transformer core was dipped ina bundling solution and dried. The bundling solution used was a partialcondensate obtained from diphenyltriethoxy-silane andmonoethyltriethoxysilane in a 1:9 ratio. The coating treatment wasperformed three times interposed with drying by warm air at 80° C. for15 minutes, then the coating was dried to form a bundling film.

By applying the present invention to a transformer core, it is possibleto operate at even 200° C., improve the rigidity of the core, and reducethe noise by 3 dB.

EXAMPLE 12

The present invention was used to produce a core with a slot which wasused for a reactor for a booster chopper. As shown in FIG. 9, a woundcore 21 was formed and dipped in a bundling solution comprised of apartial condensate obtained from diphenyldiethoxy-silane andtetramethoxysilane in a 1.5:8.5 ratio and dried in that state. The corestack was bundled while maintaining that shape. Next, the slot 22 wasformed by holding the area near the formation of the slot and cutting.On the other hand, the winding to be inserted into the cut wound corewas obtained in advance by winding and shaping wire with the bundlingsolution deposited and dried on its surface, then again dipping it intothe bundling solution and drying. Next, the formed and wound wasinserted into the cut core and the two cut parts of the core made toface each other at the cut part to provide a slot. To maintain the slot,a nonmagnetic insulator 23 was inserted, then the winding 24 wasattached. In this state, the assembly was again inserted into thebundling solution to form a bundling film 25 which was then dried.

This bundling film can at least breakdown a temperature up to 500° C.This reactor can sufficiently operate up to the temperature which theparts other than the reactor can breakdown. The core itself is high inrigidity. The slot, which becomes a cause behind noise and vibration, isalso comprised of an integral structure. Therefore, the noise can bereduced.

EXAMPLE 13

An oriented magnetic steel sheet was punched and the pieces helicallyformed for producing an integral circular armature core for an 8-polemotor. The helical cores were stacked while rotated, the assembly dippedin a bundling solution comprised of a partial condensate obtained frommonomethyltrimethoxysilane and tetramethoxysilane in a 1:1 ratio to givea film thickness after drying of 15 μm, then dried for fastening toproduce an armature core. Next, this was strain annealed at 800° C.After this, the bundling solution was deposited on the surface of thewinding, then the winding was dried at room temperature and attached tothe armature core to produce an armature. The wound core of the orientedmagnetic steel sheet had peaks in the rolling direction of the orientedmagnetic steel sheet and was extremely superior in the magneticproperties of the peaks, so the motor iron loss could be reduced. Withthe winding, the surface coating peeled off. With the treatment of thepresent invention, however, a surface coating was formed even at thepeeled coating parts and so problems could be avoided. Further, thearmature dipped in the bundling solution and dried for fastening couldbe strain annealed at 800° C., so the strain due to the winding could beremoved and the properties of the oriented magnetic steel sheet materialmade good use of.

EXAMPLE 14

The present invention was used to produce a simple small-sized 500° C.heating furnace.

As the bundling solution, a partial condensate obtained frommonomethyltrimethoxysilane and tetramethoxysilane in a 1:1 ratio wasused. This bundling solution was deposited on the surface of heaterwires. The heater wires were dried at room temperature and arranged onthe surface of the inside wall of the heating furnace. The entire insidewall member was again dipped in the bundling solution and dried toprepare an inside wall member with a heater. The heater-equipped insidewall member was then used to produce a heating furnace. The heater wiresfaced the inside of the furnace, but the surfaces of the heater wireswere formed with dried coatings of the bundling solution and thereforethe effect of electrical insulation could be maintained up to a hightemperature. This heating furnace is simple in structure and suitablefor a small-sized heating furnace.

EXAMPLE 15

The present invention was used to produce a bobbin-less movable coil ofa voice coil motor for an HDD. As the bundling solution, a partialcondensate solution obtained from monomethyltrimethoxysilane andtetramethoxysilane in a 1:1 ratio was used. This bundling solution wasdeposited on the surface of a rectangle aluminum conductor. Therectangle aluminum conductor was dried at room temperature and woundinto a motor coil. Next, the entire formed coil was again dipped intothe bundling solution and dried to produce a movable coil. The fasteningand insulation by the bundling solution used in the present example didnot pose problems even at the melting point of aluminum and wereadvantageous in terms of mechanical vibration and strength as well,which become problems in movable coils of voice coil motors.

EXAMPLE 16

A four-pole IPM (implanted magnet) motor was produced by the armaturecore produced in Example 16 and the IPM rotor using the presentinvention. This motor was controlled in torque at a low speed. Thebundling solution used was a mixed solution of tetramethoxysilane,monomethyltrimethoxysilane, and diphenyldiethoxysilane in a 2:1:1 ratio.This was dried to form a bundling film.

A magnetized FeNdB sintered magnet was dipped in the bundling solutionand dried. As shown in FIG. 8, this magnet 12 was inserted in to the IPMrotor core 11. The rotor core with the magnet inserted was also dippedin the bundling solution. The excess bundling solution was removed whilespraying compressed gas, then the core was press fit over a shaft 13.This assembly was then dried to form the bundling film 14 of the partialcondensate. Use of the present invention for the IPM rotor served bothto fasten the magnet and treat the surface of the magnet, improved theheat conductivity and insulation between the magnet and the core,suppressed the rise in temperature of the magnet, and suppressedshort-circuiting current between the magnet and core. The clearancebetween the rotor and shaft was filled by the bundling film and servedto suppress the rise in temperature of the rotor. The temperature riseof the FeNdB sintered magnet could also be suppressed and the reductionof magnetization of the magnet could also be suppressed.

EXAMPLE 17

The present invention was used to produce a two-pole induction motor.The bundling solution used was monomethylmethoxysilane. This was driedto form a bundling film. The stator core is an integral punched coreprovided with calking for provisional fastening at three locations atequal distances in the circumferential direction 2 mm from the outercircumference. The slot of the core was covered by insulation paper, thearmature winding attached, then the entire armature was dipped in thebundling solution. Next, 100° C. hot air was blown from the clearanceside with the rotor to blow away solution deposited on the peak parts inexcess to reduce the film thickness of the clearance surface to lessthan 0.1 mm. Next, this was dried to form a bundling film. The 100° C.hot air had the effect of speeding up the drying.

If using the present invention, bundling of the stacked core,suppression of short-circuiting current, reduction of noise by reductionof the vibration at the peak parts, higher output by high heat release,and lower resistance loss (suppression of increased resistance due totemperature rise) can be expected.

EXAMPLE 18

A wound transformer core provided with a winding was dipped in abundling solution and dried. The bundling solution used was a modifiedsilicone polymer, that is, an epoxy-modified polymer. This was dried toform a bundling film.

By applying the present invention to a transformer core, the rigidity ofthe core was improved and the noise reduced by 3 dB.

EXAMPLE 19

In Example 7, the stator was dipped in a bundling solution and dried forstacking and bundling, then was annealed at 750° C. This annealingreduced the motor iron loss by 8%.

EXAMPLE 20

The present invention was used to produce a core with a slot which wasused for a reactor for a booster chopper. As shown in FIG. 9, a woundcore 21 was formed and dipped in a bundling solution and dried in thatstate. The core stack was bundled while maintaining that shape. Next,the slot 22 was formed by holding the area near the formation of theslot and cutting to form the slot. To maintain the slot, a nonmagneticinsulator 23 was inserted, then the winding 24 was attached. In thisstate, the assembly was again inserted into the bundling solution toform a bundling film 25 which was then dried.

This reactor featured a high rigidity of the core itself. Further, theslot, which becomes a cause behind noise and vibration, was alsocomprised of an integral structure. Therefore, the noise could bereduced.

EXAMPLE 21

An oriented magnetic steel sheet was punched and the pieces helicallyformed for producing an integral circular armature core for an 8-polemotor. The helical cores were stacked while rotated, and the assemblydipped in a bundling solution to dry to fasten it and produce anarmature core. The wound core of the oriented magnetic steel sheet hadpeaks in the rolling direction of the oriented magnetic steel sheet. Themagnetic properties of the peaks were extremely superior, therefore themotor iron loss could be reduced. With this winding, peeling of thesurface coating occurred, but with the treatment of the presentinvention a surface coating was also formed on the peeled coating partand therefore problems could be avoided.

EXAMPLE 22

A polygon mirror motor for a laser beam printer was produced on aprinted circuit board using a magnetic steel sheet. The printed circuitboard was a laminate of two magnetic steel sheets. An armature coil wasfastened on this. The armature coil and board were fastened and themagnetic steel sheets were bundled using the bundling method of thepresent invention. The two magnetic steel sheets were stacked, then thearmature coil fastened and the assembly dipped in the bundling solutionand dried by hot air for fastening. The bundling solution used wasmaintained in bundling power even with a rise of the coil temperatureand free from the problem of out gas, so the bundling of the stack ofthe two magnetic steel sheets of the printed circuit board and thefastening of the armature coil on the printed circuit board weresufficiently maintained even if the temperature rose due to motoroperation. Since there was no problem with out gas either, there was noproblem with fogging of the mirror.

EXAMPLE 23

A wound core of a transformer was produced by an amorphous magneticmaterial, dipped in a bundling solution, then dried while holding itsshape. This core was used to produce a transformer, fit into a magneticshield case, and used while drying the transformer. For the magneticshield case, use was made of an assembly of panels comprised ofnanocrystal high permeance material stacked, dipped in the same bundlingsolution, and dried for fastening. The amorphous material was extremelythin, so the core or shield plate was low in rigidity, but the memberscould be simple joined and increased in rigidity by the bundling methodof the present invention, fastening of the core or shield plates becameeasy, and fragments of amorphous metal or nanocrystals were alsounlikely to occur.

INDUSTRIAL APPLICABILITY

If there is a short-circuit with the secondary conductors, case, bolts,etc. at the end faces or surface of a core used for a motor or otherenergy converting device, the loss of the device will increase, thetorque, thrust, or output will fall, and the performance will vary.Therefore, treatment of the end faces and surface of the core forinsulation is extremely important for the improvement and stabilizationof the performance of the device. The ability to perform this insulationtreatment easily in a short time is industrially valuable.

According to the present invention, it is possible to treat the endfaces of a core to give insulation extremely superior in effect ofimprovement of the insulation, corrosion resistance, adhesiveness, heatresistance, and magnetic properties at a low temperature and in a shorttime without cleaning to remove the punching oil, annealing, or otherpre-treatment.

Therefore, this method is effective for the improvement andstabilization of the performance of the device. The process is simple,therefore the cost can be lowered and the technique is extremelyvaluable industrially. Improvement of the efficiency and lowering of theloss of a device are important in terms of energy and the environment.Use of the present invention is therefore also valuable socially. Abroad range of applications may be considered such as for householdelectrical appliances, factory automation devices, office automationdevices, automobiles, trains, etc.

Further, the present invention takes note of the fact that if there is ashort-circuit with the secondary conductors, case, bolts, etc. at theend faces or surface of a core used for various types of transformers,the loss of the device will increase and damage will occur. Further, itbecomes a cause of fluctuations in performance. Therefore, treatment ofthe end faces and surface of the core for insulation is extremelyimportant for the improvement and stabilization of the performance ofthe device. The ability to perform this insulation treatment easily in ashort time is industrially valuable. Further, this can contribute to theimprovement of the properties such as the heat resistance required inthe case of annealing after the processing.

Further, the high temperature operating electrical apparatus accordingto the present invention can achieve a higher heat-resistancetemperature of the windings. The fastening and bundling of the windingand the core and yoke comprised of the magnetic materials also do notbecome a problem at a high temperature. Therefore, it is possible togreatly increase the current flowing through the winding and increasethe output of the device. Further, the high temperature operatingelectrical apparatus can be used at a high temperature location.

1. A core of a motor, actuator or generator having a superior end face insulation characterized in that end faces of the core have an insulation coating of an average film thickness of at least 2.0 μm comprised of at least 30 wt % of a silicon compound converted to SiO₂, wherein said insulation coating is an outermost surface of the end faces of the core, and at least one electrically conductive member external to the core contacts with a portion of the insulation coating of at least one end face of the core.
 2. A core of a motor, actuator or generator having a superior end face insulation as set forth in claim 1, characterized in that an average film thickness of said insulating coating is more than 10 μm and a breakdown voltage is at least 30V.
 3. A core of a motor, actuator or generator having a superior end face insulation as set forth in claim 1 or 2, characterized in that said insulating coating has a heat resistance in air of at least 400° C.×1 hour.
 4. A core of a motor, actuator or generator having a superior end face insulation as set forth in claim 1, characterized in that the body of said core is comprised of non-oriented magnetic steel sheet. 